Name: SDC Uniflex Series 55-F Heavy Duty 3/4" Mortise Electric Strike with Field Reversible Fail-Safe/Fail-Secure Operation
Brand: SDC
SKU: 55-FQxDBM-R
Price: 495.78 USD
Availability: InStock

Product Overview
FAQs

SDC Uniflex Series 55-F Heavy Duty 3/4"; Mortise Electric Strike with Field Reversible Fail-Safe/Fail-Secure Operation

Professional Access Control Solution for High-Security Applications

The SDC Uniflex Series 55-F electric strike delivers heavy-duty performance for access control of cylindrical locksets, mortise locksets with or without deadbolts, and mortise exit devices. Designed for 3/4"; throw latchbolts and up to 1"; throw deadbolts, this strike features field selectable dual voltage operation at 12/24 VDC with field reversible fail-safe/fail-secure functionality. Built with stainless steel components and heavy cast housing, it’s rated for 1,000,000 endurance cycles and provides 2500 holding force for demanding commercial applications.

Professional Features & Benefits

Heavy-Duty Durability: Tested to 1,000,000 endurance cycles for long-term reliability in high-traffic commercial applications.
Superior Holding Force: 2500 holding force with 70 ft-lbs dynamic strength provides exceptional security performance.
Flexible Power Options: Field selectable dual voltage operation at 12/24 VDC with voltage and current spike protection for various system requirements.
Field-Reversible Operation: Field selectable fail-safe/fail-secure configuration allows adaptation to specific security requirements without replacement.
Heavy-Duty Construction: Stainless steel components with heavy cast housing body and keeper provide exceptional durability and corrosion resistance.
Universal Compatibility: Accepts 3/4"; throw latchbolts and up to 1"; throw deadbolts for versatile lockset compatibility.
Retrofit-Friendly Design: Fits existing ANSI 4-7/8"; strike prep with no centerline relocation required for easy installation.
Professional Certifications: UL 1034 Burglary-Resistant, UL 10C Fire Tests, and ANSI/BHMA A156.31 Grade 1 certified for code compliance.

Technical Specifications

Commercial/Residential: Commercial
Department: Door Hardware
Door Type: Hollow Metal
Dynamic Strength: 70 ft-lbs
Electronic: Yes
Endurance Cycles: 1,000,000
Holding Force: 2500
Latch Throw: 3/4";
Product Category: Electronic Access Controls
Product Group: Electronic Access Controls
Product Model: 55-F
Product Subgroup: Electric Strikes
Product Type: Electric Strikes
Product Voltage: 12/24 VDC
Series: 55 Series
Subcategory: Electric Strikes
Switch Device: SPDT

Professional Applications

Commercial Building Security Systems
Healthcare Facility Access Control
Educational Institution Safety Systems
Government and Municipal Buildings
Industrial Facility Monitoring
High-Security Retrofit Applications
Multi-Tenant Commercial Properties

Tamper-Resistant Design

The SDC 55-F features corrosion and tamper resistant construction with internally mounted solenoid and stainless steel components. The heavy cast housing body provides additional protection against unauthorized access attempts while maintaining reliable operation in demanding environments.

Why Choose SDC Quality?

SDC electric strikes deliver professional-grade reliability with stainless steel construction and heavy cast housing rated for 1,000,000 endurance cycles. UL 1034 Burglary-Resistant certification and ANSI/BHMA A156.31 Grade 1 rating ensure code compliance and performance standards. Engineered for demanding commercial applications where dependable access control performance is essential.

Manufacturer Resources

SDC Full Catalog

Product Specs

Subcategory:: Electric Strikes
Series:: 55 Series
Dynamic Strength:: 70 ft-lbs
Endurance Cycles:: 1,000,000
Product Group:: Electronic Access Controls
Product Subgroup:: Electric Strikes
Product Type:: Electric Strikes
Latch Throw:: 3/4"
Commercial/Residential:: Commercial
Electronic:: Yes
Door Type:: Hollow Metal
Holding Force:: 2,500 lbs
Product Model:: 55-F
Product Voltage:: 12/24VDC
Switch Device:: SPDT
Product Category:: Electronic Access Controls
Department:: Door Hardware

SDC 55-FQxDBM-R – Frequently Asked Questions

1) Will the SDC 55-F electric strike drop into an existing ANSI strike prep in a hollow metal frame?

Yes. The Uniflex 55-F fits an existing ANSI 4-7/8 inch strike prep with no centerline relocation, which is why it gets specified on retrofits where cutting the frame is not an option. It is a mortise strike built for hollow metal frames, so the prep it drops into is the standard 4-7/8 inch ANSI cutout already in most commercial steel frames.

2) What locks does the SDC 55-F electric strike work with, and will it take a deadbolt?

The 55-F releases cylindrical locksets, mortise locksets with or without deadbolts, and mortise exit devices. It accepts latchbolts up to 3/4 inch throw and deadbolts up to 1 inch throw. If the mortise lock on your opening throws a deadbolt longer than 1 inch, the keeper will not clear it and this is the wrong strike.

3) Do I have to order a fail-safe or fail-secure version of the SDC 55-F, or can I set it in the field?

You set it in the field. Fail-safe and fail-secure are field reversible on the 55-F, so one part covers both, and you can flip an opening later without swapping the strike. Same story with power: it is field selectable 12 or 24 VDC, so it drops onto either bus. Fail-safe unlocks when power drops (used on egress-critical openings tied into fire alarm release); fail-secure stays locked through a power loss.

4) Does the SDC 55-F electric strike need to be ordered handed?

Handing matters here. The 55-F is ordered left hand or right hand, so determine the door's hand before you place the order. It is not a field reversible keeper the way the fail-safe/fail-secure setting is.

5) Is the SDC 55-F strike fire rated and Grade 1?

The 55-F carries UL 10C fire test certification, UL 1034 burglary resistance, and ANSI/BHMA A156.31 Grade 1. That combination is what a facility spec usually calls for on a rated opening: A156.31 Grade 1 is the top performance tier for electric strikes, and UL 10C is the positive pressure fire door test.

6) What monitoring options can I get on the SDC 55-F, and how do I tie it into an access control panel?

Four monitoring configurations are orderable, plus a plain strike with none: DBM for deadbolt status, LBM for latch status, LBMLCM for latch and keeper deadlocked status, and LBMLCM DBM for latch, keeper deadlocked, and deadbolt status together. The monitor switch is SPDT, so you have a common, normally open, and normally closed leg to land at the panel for door position or forced/propped alarm logic. Pick the monitoring at order time, since it is not something you add to a strike already installed.

7) I need an electric strike for an aluminum storefront jamb, not hollow metal - what do I use instead of the SDC 55-F?

The 55-F is built for hollow metal doors, so an aluminum stile-and-rail storefront jamb calls for a different device. The Adams Rite 7100 Series is an electric strike for aluminum jambs with a flat faceplate measuring 1-1/4 inch by 4-7/8 inch, and the Adams Rite 7160 is also an aluminum jamb strike with a 1-1/4 inch by 4-7/8 inch faceplate. Both are non fire rated, so on a labeled aluminum opening neither one applies. If the jamb turns out to be hollow metal or wood rather than aluminum, the Adams Rite 7170 covers those with the same 1-1/4 inch by 4-7/8 inch faceplate.

8) My latchbolt only throws 5/8 inch - is the SDC 55-F still the right strike?

The 55-F is built around a 3/4 inch latch throw and takes deadbolts up to 1 inch throw. For a 5/8 inch latchbolt there are strikes cut for that projection: the Adams Rite 7240 is a fire rated electric strike for cylindrical locksets with 5/8 inch latchbolt projection, and the Hager 2925 is an electric strike with a 5/8 inch latch and field reversible fail safe/secure operation, which keeps the same reversible function the 55-F offers. Trine 004 accepts up to 5/8 inch throw on an 8-16VAC fail secure basis with a 6-1/4 inch by 1-3/8 inch faceplate, so confirm your jamb prep before choosing it.

9) Which electric strikes besides the SDC 55-F give me latchbolt monitoring for the access control panel?

The 55-F offers monitoring as a device option: LBM latch status, DBM deadbolt status, LBMLCM latch and keeper deadlocked status, and the combined LBMLCM DBM, reporting through an SPDT switch. Among other strikes, the Dortronics 3300 Series has a latch bolt sensing switch and runs 12/24VDC with a strike plate for ANSI prep at 4-7/8 inch by 1-1/4 inch. The Hager 2945 is a fire rated rim exit strike with field selectable fail safe/fail secure and a latchbolt monitor, and the Camden CX-ED1799L-8 is a dual monitor Grade 1 fire rated strike supplied with 8 faceplates. Decide by what you are monitoring: the 55-F is the one of these that reports deadbolt status as well as latch.

10) What is the closest heavy duty Grade 1 electric strike to the SDC 55-F if I need a different brand on the same opening?

The Von Duprin 4211 32D is the nearest peer: it is a Grade 1, heavy duty, fire rated electric strike for cylindrical locks with 12/24 VDC field-selectable voltage, matching the 55-F on dual voltage 12/24VDC and Grade 1 heavy duty class. The difference to check before you order is scope of lockset: the 55-F handles cylindrical locksets, mortise locksets with or without deadbolts, and mortise exit devices, while the 4211 is specified for cylindrical locks. For an opening running a mortise lock with a deadbolt, the Von Duprin 6210 is the mortise-lock counterpart, though it is a 24 VDC fail-secure device rather than a field reversible fail-safe/fail-secure one.

11) I do not want to cut the frame - is there an electric strike that avoids the SDC 55-F's prep work?

The 55-F is designed to drop into existing ANSI 4-7/8 inch strike prep with no centerline relocation, so on a frame already prepped to ANSI it is not a cutting job. Where the frame has no ANSI prep at all, the Locknetics NC450 is a no cut electric strike, and the Camden CX-ED1689L-4 is a fire rated low profile universal strike shipped with 4 faceplates to cover varying preps. Compare on what your frame already has: the 55-F assumes ANSI prep, those two are aimed at frames that do not.

12) Is the Adams Rite 7100 a drop-in replacement for the SDC 55-F on a fire rated door?

No. The Adams Rite 7100 is an aluminum jamb strike with a 1-1/4 inch by 4-7/8 inch flat faceplate and is not fire rated, so despite the familiar 4-7/8 inch faceplate dimension it is not an equivalent for the 55-F, which carries UL 10C fire test and UL 1034 burglary-resistant listings along with ANSI/BHMA A156.31 Grade 1. On a labeled opening the fire rated peers are the ones to look at: Hager 2930, a fire rated Grade 1 strike for cylindrical and mortise locks with 12/24VDC dual voltage and field reversible fail safe/secure operation, or the Camden CX-ED1410/CX-ED1420 universal Grade 1 ANSI fire-rated strikes.

13) I am standardizing a facility on one electric strike - which Grade 1 strikes cover both mortise and cylindrical locks?

The SDC 55-F takes cylindrical locksets, mortise locksets with or without deadbolts, and mortise exit devices on one 3/4 inch throw platform, at ANSI/BHMA A156.31 Grade 1. For the same breadth from another maker, the Von Duprin 6400 32D is a Grade 1 heavy duty modular strike for mortise or cylindrical locks in satin stainless steel, rated 3-hour UL 10C in fail-secure, and the Hager 2930 is a fire rated Grade 1 strike for cylindrical and mortise locks with 12/24VDC dual voltage. The 6400 is specified fail-secure, while the 55-F and the 2930 are field reversible between fail safe and fail secure, which matters if some of your openings need to release on fire alarm.

14) My opening runs surface vertical rods or a double door - can I still use the SDC 55-F?

The 55-F is built for cylindrical locksets, mortise locksets with or without deadbolts, and mortise exit devices with a 3/4 inch latch throw. Surface vertical rod and double door openings have their own devices: the HES Folger Adam 310-4-2 is a complete electric strike pac for surface vertical rods, Grade 1, and the Rockwood electric strike for double doors uses a 3/4 keeper and is fire rated Grade 1 in the 310-1 Series. If the opening is a rim exit device, the Hager 2945 is a fire rated rim exit strike with field selectable fail safe/fail secure.

15) Can I run the SDC 55-F on a 16-24VAC power supply, or do I need a different strike?

The 55-F is a 12/24 VDC device, field selectable between the two voltages, with voltage and current spike protection. If the opening is fed by an AC supply, the Trine 2001 is a 16-24VAC/DC fail secure strike with a 5-7/8 inch by 1-1/4 inch faceplate accepting up to 5/8 inch throw, and the Trine 004 runs 8-16VAC fail secure with a 6-1/4 inch by 1-3/8 inch faceplate, also up to 5/8 inch throw. Both are fire rated and both are fail secure only, so the field reversibility and the 3/4 inch throw of the 55-F do not carry over.

16) Is the SDC 55-F strong enough for a high traffic entrance or a school corridor?

The numbers behind it: 2,500 lbs static holding force, 70 ft-lbs dynamic strength, and 1,000,000 endurance cycles, with stainless steel components and a heavy cast housing body and keeper. That cycle count is the reason it lands on main entries, healthcare corridors, and school openings that get hit all day rather than on a low-use back office door.

17) What are the closest alternatives to the SDC 55-F for a mortise lock on a fire rated opening?

Three sit in the same lane. The Von Duprin 6210 is a heavy duty Grade 1 mortise strike, UL 10C fire rated, but it is 24 VDC fail-secure only, so no field voltage or fail-safe selection. The Von Duprin 6400 is Grade 1, heavy duty, fail-secure, with a 3-hour UL 10C rating in that configuration. The Securitron MUNL mortise UnLatch strike is Grade 1 and fire rated. Where the 55-F separates itself is field reversible fail-safe/fail-secure plus field selectable 12/24 VDC in one part, which matters when you are standardizing stock across a building instead of ordering per opening.

18) What is a simpler electric strike than the SDC 55-F for a light duty interior door?

The 55-F is a commercial heavy duty device rated to 1,000,000 endurance cycles with 2,500 lbs holding force and 70 ft-lbs dynamic strength, which is more strike than a low traffic interior opening needs. The Trine 001 Series is a fail-secure light commercial electric strike with a 5-7/8 inch by 1-1/4 inch faceplate, and the RCI 15BS is an economy electric strike for special offset latch entry with fail-secure operation. Both are non fire rated and fail-secure only, so they do not give you the field reversible fail-safe/fail-secure selection the 55-F does, and neither belongs on a labeled door.

19) Which other heavy duty electric strikes come in satin stainless to match the SDC 55-F?

The 55-F is offered in 630 satin stainless steel and 629 bright stainless among its nine finishes, along with brass and bronze options including 605 bright brass, 613 oil rubbed bronze and 626 dull chrome. If you are matching stainless across an opening from another maker, the Locknetics MDS100 is a heavy duty strike in US32D, the Locknetics MS100 is heavy duty in US32D, and the Von Duprin 6400 32D is a Grade 1 heavy duty modular strike in satin stainless steel. The 55-F is the one of this group carrying brass and bronze finishes as well, which matters where the existing hardware is not stainless.

20) What is the difference between the SDC 55-F and the Securitron MUNL for a mortise lock opening?

Both are Grade 1 fire rated devices for mortise applications. The Securitron MUNL is a mortise UnLatch electric strike, Grade 1 and fire rated. The SDC 55-F is a mortise electric strike with a 3/4 inch latch throw that also accepts deadbolts up to 1 inch, runs field selectable 12/24 VDC, is field reversible between fail-safe and fail-secure, and is rated 1,000,000 endurance cycles with 2,500 lbs holding force. Choose on the deadbolt: if the mortise lock on your opening throws a deadbolt you want the strike to release, the 55-F is specified for mortise locksets with deadbolts.

21) I need a strike body that handles 1/2 inch, 5/8 inch or 3/4 inch latchbolts - how does that compare to the SDC 55-F?

The HES Folger Adam 310-1(X) is an electric strike body that covers 1/2 inch, 5/8 inch or 3/4 inch throw latchbolts, fire rated and Grade 1. The SDC 55-F is specified for 3/4 inch throw latchbolts and deadbolts up to 1 inch, so on a mixed retrofit where latch projections vary door to door the 310-1(X) spans the range, while the 55-F is the one that also addresses deadbolt-equipped mortise locks and mortise exit devices. Accessory and faceplate support for the HES 1500 and 1600 Series strikes is available separately, both fire rated Grade 1 lines.

22) What finish should I order on the SDC 55-F to match the rest of my door hardware?

Nine finishes are available: 605 bright brass, 606 dull brass, 611 bright bronze, 612 dull bronze, 613 oil rubbed bronze, 625 bright chrome, 626 dull chrome, 629 bright stainless, and 630 satin stainless steel. On commercial openings 630 satin stainless is the usual match to existing levers and exit devices, and 626 dull chrome pairs with older brushed chrome trim. The strike faceplate is the only visible part, so match it to the frame side hardware rather than the door.

23) Can I use the SDC 55-F on an exterior gate or an outdoor opening?

The 55-F is a commercial mortise strike specified for hollow metal frames, with corrosion resistant stainless components and an internally mounted solenoid. For a gate specifically, the Camden CX-ED1959 Series is the outdoor rated gate strike to look at instead, though it is not fire rated, so it belongs on a non-rated exterior application.

24) Will the SDC 55-F survive being wired into a system with voltage spikes from other devices?

The 55-F includes voltage and current spike protection on its dual voltage circuit, which is what keeps a shared 12 or 24 VDC bus running maglocks, strikes, and readers from taking out the solenoid. The solenoid itself is mounted internally in the cast housing, so it is not exposed at the frame cutout.

How fast can I get the SDC 55-FQxDBM-R delivered?

Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.

Can I return it if it doesn’t work for me?

Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.

Does the SDC 55-FQxDBM-R come with a warranty?

Absolutely. The SDC 55-FQxDBM-R is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.

How do I get technical support or installation help for the SDC 55-FQxDBM-R?

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SDC Uniflex Series 55-F Heavy Duty 3/4" Mortise Electric Strike with Field Reversible Fail-Safe/Fail-Secure Operation

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