SDC 55-D Uniflex Series 55-D H...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$692.00
$495.78
SDC SDC 55-D Uniflex Series - Heavy Duty 3/4” Mortise - Deadlatch Below with Deadbolt Faceplate Latchbolt Electric Strikes, Field Reversible Failsafe/Failsecure SDC-55-D

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

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Model: 55-DQxDBM-R
$692.00
$495.78
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In Stock (leaves warehouse same day if ordered before 3pm ET)

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

Professional Access Control Solution for Hollow Metal Frame Applications

The SDC Uniflex Series 55-D electric strike delivers heavy-duty access control performance for cylindrical locksets, mortise locksets with or without deadbolts, and mortise exit devices. Engineered with a 3/4"; latchbolt capacity and up to 1"; deadbolt throw accommodation, this strike features field selectable dual voltage operation at 12/24 VDC with field reversible fail-safe/fail-secure functionality. The stainless steel construction and heavy cast housing provide exceptional durability rated for 1,000,000 endurance cycles with 2500 holding force and 70 ft-lbs dynamic strength.

Professional Features & Benefits

  • Heavy-Duty Durability: Tested to 1,000,000 endurance cycles with 2500 holding force and 70 ft-lbs dynamic strength for reliable performance in high-traffic commercial applications.
  • Flexible Power Options: Field selectable dual voltage operation at 12/24 VDC with voltage and current spike protection for versatile system integration.
  • Fail-Safe/Fail-Secure Operation: Field reversible configuration allows adaptation to specific security requirements with SPDT switch device functionality.
  • 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 with interchangeable faceplate design for various lock configurations.
  • Retrofit-Friendly Installation: Designed to retrofit existing ANSI 4-7/8"; strike prep without centerline relocation for easy upgrades.
  • Professional Certifications: UL 1034 Burglary-Resistant Electric Locking Mechanisms, UL 10C Positive Pressure Fire Tests, and ANSI/BHMA A156.31 Grade 1 certified.
  • Tamper-Resistant Design: Internally mounted solenoid with corrosion and tamper resistant construction ensures secure operation.

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-D
  • 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
  • Educational Institution Access Control
  • Healthcare Facility Security
  • Government and Municipal Buildings
  • Industrial Facility Access Points
  • Multi-Tenant Residential Properties
  • Retail Loss Prevention Systems

Why Choose SDC Quality?

SDC electric strike products deliver professional-grade reliability with stainless steel construction and heavy cast housing rated for 1,000,000 endurance cycles with 2500 holding force capacity. UL 1034, UL 10C, and ANSI/BHMA A156.31 Grade 1 certifications ensure compliance with the highest industry 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-D
Product Voltage:
12/24VDC
Switch Device:
SPDT
Product Category:
Electronic Access Controls
Department:
Door Hardware

SDC 55-DQxDBM-R – Frequently Asked Questions

1) Will the SDC 55-D electric strike drop into an existing ANSI 4-7/8 inch strike prep?
Yes. The Uniflex 55-D retrofits existing ANSI 4-7/8 inch strike prep without relocating the centerline, so an upgrade from a mechanical strike or an older electric strike in a hollow metal frame is a swap rather than a re-prep. The faceplate is interchangeable to match the lock configuration you are working with.
2) What locks will the SDC 55-D electric strike work with?
Cylindrical locksets, mortise locksets with or without a deadbolt, and mortise exit devices. The keeper takes latchbolts up to 3/4 inch throw and deadbolts up to 1 inch throw, so a mortise lock with a deadbolt above or below the latch is handled by the same strike. If your lock throws a latch longer than 3/4 inch, this is not the right keeper.
3) Do I have to order the SDC 55-D as fail-safe or fail-secure, and can I change it later?
Order either way, because it is field reversible. The 55-D switches between fail-safe (unlocked on power loss) and fail-secure (locked on power loss) in the field, so one part number covers an egress-side opening and a secured stairwell alike. Voltage is the same story: 12 or 24 VDC is field selectable on the same unit, with spike protection built in.
4) Does handing matter when ordering an SDC 55-D strike?
Yes, handing matters. The 55-D is ordered left hand or right hand, so determine the door's hand at the opening before you order. There is no single non-handed version.
5) What monitoring options can I get on the SDC 55-D strike?
Four monitoring configurations plus a no-monitor version. DBM reports deadbolt status, LBM reports latch status, LBMLCM reports latch and keeper deadlocked status, and LBMLCM DBM combines latch, keeper deadlocked and deadbolt status. Switching is SPDT. If your access control panel needs door-secure confirmation before it will arm or report, specify the monitor option at order time; it is not something you add to the strike later.
6) Is the SDC 55-D electric strike rated for a fire door?
The 55-D carries UL 10C Positive Pressure Fire Tests, along with UL 1034 for burglary-resistant electric locking mechanisms and ANSI/BHMA A156.31 Grade 1. For a fire opening, the strike must be applied fail-secure, since a fail-safe strike releases the latch on power loss.
7) The jamb is aluminum, not hollow metal - is the SDC 55-D the right strike?
The SDC 55-D is specified for hollow metal frames. For aluminum jambs, the Adams Rite 7100 Series is an electric strike for aluminum jambs with a flat 1-1/4 inch by 4-7/8 inch faceplate, and the Adams Rite 7160 is likewise for aluminum jambs with a 1-1/4 inch by 4-7/8 inch faceplate. Both Adams Rite units are listed as not fire rated. Adams Rite also builds the 7170 for hollow metal and wood jambs with the same 1-1/4 inch by 4-7/8 inch faceplate.
8) What is a direct alternative to the SDC 55-D for a mortise lock opening that needs Grade 1 and a fire rating?
The Von Duprin 6210 is an electric strike built for mortise locks, listed as heavy duty, Grade 1, and UL 10C fire rated, running 24 VDC fail-secure. The SDC 55-D covers mortise locksets with or without deadbolts and mortise exit devices, and it carries UL 1034, UL 10C and ANSI/BHMA A156.31 Grade 1 with field selectable 12/24 VDC and field reversible fail-safe/fail-secure. The practical split is voltage and function flexibility: the 6210 is a single-voltage fail-secure unit, while the 55-D is set in the field for either voltage and either failure mode.
9) The opening has a cylindrical lockset rather than a mortise lock - what should be used instead of the SDC 55-D?
The Von Duprin 4211 32D is an electric strike for cylindrical locks, Grade 1, heavy duty, fire rated, with 12/24 VDC field-selectable voltage. The Hager 2930 is a fire rated Grade 1 strike for cylindrical and mortise locks with 12/24 VDC dual voltage and field reversible fail safe/secure operation. The SDC 55-D itself accepts cylindrical locksets as well as mortise locksets and mortise exit devices, so a cylindrical latch alone does not rule it out; the 55-D distinguishes itself with 3/4 inch latchbolt capacity and accommodation for up to a 1 inch deadbolt throw.
10) Which electric strikes take a 3/4 inch throw latchbolt like the SDC 55-D does?
The HES Folger Adam 310-1(X) strike body accepts 1/2 inch, 5/8 inch or 3/4 inch throw latchbolts and is Grade 1 and fire rated. The Rockwood double door electric strike uses a 3/4 keeper and is Grade 1, fire rated, in the 310-1 Series. The SDC 55-D has a 3/4 inch latch throw and additionally accommodates deadbolt throw up to 1 inch. Strikes such as the Adams Rite 7240, at 5/8 inch latchbolt projection, and the Trine 2001 at up to 5/8 inch, are built around a shorter latch projection.
11) What is the difference between the SDC 55-D and the Von Duprin 6400 for a job that mixes mortise and cylindrical locks?
The Von Duprin 6400 32D is a Grade 1 modular electric strike for mortise or cylindrical locks, fail-secure, in satin stainless steel, heavy duty, with a 3-hour UL 10C fire rating in fail-secure. The SDC 55-D covers cylindrical locksets, mortise locksets with or without deadbolts and mortise exit devices through an interchangeable faceplate design, and its failure mode is field reversible rather than fixed fail-secure. The 55-D also comes in nine finishes including 630 satin stainless steel and 626 dull chrome.
12) Which electric strikes offer latch or deadbolt monitoring the way the SDC 55-D does?
The SDC 55-D is ordered with monitoring built in: DBM deadbolt status, LBM latch status, LBMLCM latch and keeper deadlocked status, or LBMLCM DBM combining both. Among other strikes, the Dortronics 3300 Series has a latch bolt sensing switch at 12/24VDC with a strike plate for ANSI prep at 4-7/8 by 1-1/4 inch. The Camden CX-ED1799L-8 is a fire rated dual monitor Grade 1 strike supplied with 8 faceplates, and the Hager 2945 rim exit strike includes a latchbolt monitor.
13) The frame prep cannot be cut - what strike works where the SDC 55-D would require modification?
The Locknetics NC450 is a no cut electric strike in the NC Series. The Camden CX-ED1689L-4 is a fire rated universal low profile strike supplied with 4 faceplates, and the Camden CX-ED1410 and CX-ED1420 are universal Grade 1 ANSI fire-rated strikes. The SDC 55-D itself retrofits existing ANSI 4-7/8 inch strike prep without relocating the centerline, so an opening already cut to ANSI prep does not need a no-cut unit.
14) The system supplies AC power rather than DC - can the SDC 55-D be used?
The SDC 55-D operates on field selectable 12/24 VDC. Where the supply is AC, the Trine 004 strike runs 8-16VAC fail secure with a 6-1/4 inch by 1-3/8 inch faceplate and up to 5/8 inch throw, and the Trine 2001 runs 16-24VAC/DC fail secure with a 5-7/8 inch by 1-1/4 inch faceplate and up to 5/8 inch throw. Both Trine units are fire rated.
15) Is the SDC 55-D strong enough for a high traffic entrance that gets abused?
2,500 lbs static holding force, 70 ft-lbs dynamic strength, and 1,000,000 endurance cycles, with a heavy cast housing and keeper and stainless steel components. That is the specification set for a main entrance, a dorm, or a hospital corridor that cycles all day, not a light-duty interior office door.
16) What is a good alternative to the SDC 55-D for a mortise lock if I need a different brand?
For a mortise lock in a hollow metal frame, the Von Duprin 6210 is a Grade 1 heavy duty, UL 10C fire rated strike, though it is 24 VDC fail-secure only rather than field reversible. The Von Duprin 6400 is a Grade 1 modular strike that serves either mortise or cylindrical locks. The Securitron MUNL Mortise UnLatch is another Grade 1 fire rated mortise option. Where field reversible fail safe/secure is the reason you were looking at the 55-D, the Hager 2930 is Grade 1 fire rated for cylindrical and mortise locks with 12/24 VDC dual voltage and field reversible operation.
17) My mortise lock throws a 5/8 inch latch. Do I still need the 3/4 inch SDC 55-D?
A 3/4 inch keeper accepts a shorter latch, so a 5/8 inch throw sits inside the 55-D keeper without trouble. If you would rather buy to the exact throw, the Hager 2925 is built around a 5/8 inch latch with field reversible fail safe/secure, and the HES Folger Adam 310-1(X) strike body covers 1/2, 5/8 or 3/4 inch throw latchbolts.
18) Can one SDC 55-D strike secure a pair of doors?
No. The 55-D is a single jamb-mounted mortise strike, handed left or right, so it releases one leaf. A pair with no mullion needs a strike built for double doors, such as the Rockwood double door electric strike with a 3/4 keeper, which is Grade 1 and fire rated.
19) Does the SDC 55-D work on a mortise exit device?
Yes, mortise exit devices are among the locks the 55-D keeper is built for, along with cylindrical and mortise locksets. Note the distinction: this is a mortise strike, not a rim exit strike. If your device is a rim exit device with a surface latch, you want a rim strike instead, such as the Hager 2945 fire rated rim exit strike with field selectable fail safe/fail secure and latchbolt monitor.
20) What is a lighter-duty electric strike than the SDC 55-D for a low-traffic interior door?
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 is not fire rated. The RCI 15BS is an economy electric strike for special offset latch entry with fail-secure operation, also not fire rated. Both are fixed fail-secure. The SDC 55-D is a commercial unit rated for 1,000,000 endurance cycles with 2,500 lbs holding force and 70 ft-lbs dynamic strength, and it can be set either fail-safe or fail-secure in the field.
21) Which strikes look like alternatives to the SDC 55-D but are not complete units?
The HES 1500 and HES 1600 entries are electric strike accessories for those Grade 1 fire rated series, not standalone strikes. The HES Folger Adam 310-1(X) is a strike body for 1/2, 5/8 or 3/4 inch throw latchbolts rather than a full assembly. By contrast the HES Folger Adam 310-4-2 is a complete electric strike pac for surface vertical rods, and the SDC 55-D ships as a complete strike with a heavy cast housing body and keeper, ordered by handing, finish and device option.
22) What other heavy duty Grade 1 strikes compete with the SDC 55-D for high-traffic commercial openings?
The Alarm Controls AES-100 is a Grade 1 heavy duty electric strike in the AES Series. The Securitron MUNL Series mortise unlatch strike is Grade 1 and fire rated. The Locknetics MDS100 and MS100 are both listed as heavy duty, in the MDS and MS Series respectively, and the Locknetics CS450 is in the CS Series. The SDC 55-D carries ANSI/BHMA A156.31 Grade 1 with a 1,000,000 cycle endurance rating, 2,500 lbs holding force and 70 ft-lbs dynamic strength.
23) What finishes does the SDC 55-D Uniflex strike come in?
Nine BHMA finishes: 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. For matching an existing commercial building standard, 630 satin stainless is the usual pick on hollow metal openings and 626 the usual match to older brushed chrome lock trim.
How fast can I get the SDC 55-DQxDBM-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-DQxDBM-R come with a warranty?
Absolutely. The SDC 55-DQxDBM-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-DQxDBM-R?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the SDC 55-DQxDBM-R from ZenSupply?
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Product Reviews

  • 5
    Upgrade Your Security

    Posted by George on Feb 8th 2024

    I just wanted to share my thoughts on the SDC 55 D/E/F Series Electric Strikes. These bad boys are heavy-duty and offer top-notch security for my doors. I love the deadbolt feature for added protection. However, installation can be a bit complex, so make sure you have some DIY skills or a professional handy. Overall, worth it for the peace of mind they provide!

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