SDC 55-A Uniflex Series Heavy ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$515.00
$361.89
SDC SDC 55-A Uniflex Series - Heavy Duty 3/4” Cylindrical Faceplate Latchbolt Electric Strikes, Field Reversible Failsafe/Failsecure SDC-55-A

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

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Model: 55-AU
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$515.00
$361.89
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SDC Uniflex Series Heavy Duty 3/4"; Cylindrical Faceplate Electric Strike with Field Reversible Fail-Safe/Fail-Secure Operation

Professional Access Control Solution for Hollow Metal Frame Applications

The SDC Uniflex Series 55-A electric strike delivers heavy-duty access control for cylindrical locksets, mortise locksets with or without deadbolts, and mortise exit devices. Engineered with stainless steel components and a heavy cast housing body, this strike accepts 3/4"; throw latchbolts and up to 1"; throw deadbolts. The unit operates on 12/24 VDC with field selectable dual voltage capability and features field reversible fail-safe/fail-secure operation for flexible security configurations.

Professional Features & Benefits

  • Heavy-Duty Durability: Rated for 1,000,000 endurance cycles with 2500 holding force and 70 ft-lbs dynamic strength for demanding commercial applications.
  • Flexible Power Options: Field selectable dual voltage 12/24 VDC operation with voltage and current spike protection for reliable performance.
  • Fail-Safe/Fail-Secure Operation: Field reversible configuration allows adaptation to specific security requirements without hardware changes.
  • Universal Compatibility: Accepts 3/4"; throw latchbolts and up to 1"; throw deadbolts for use with cylindrical locksets, mortise locksets, and mortise exit devices.
  • Retrofit-Friendly Design: Fits existing ANSI 4-7/8"; strike preparation with no centerline relocation required for easy installation.
  • Stainless Steel Construction: Stainless steel components and square corner faceplate provide corrosion and tamper resistance for long-term reliability.
  • Professional-Grade Certifications: UL 1034 Burglary-Resistant Electric Locking Mechanisms, UL 10C fire rated, and ANSI/BHMA A156.31 Grade 1 certified.
  • Advanced Features: Horizontal alignment adjustment, non-handed design, interchangeable faceplate system, and internally mounted solenoid with pigtail connectors.

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-A, 55-B, 55-C
  • 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 strikes deliver professional-grade reliability with stainless steel construction and heavy cast housing rated for 1,000,000 endurance cycles with 2500 holding force. UL 1034 burglary-resistant certification and ANSI/BHMA A156.31 Grade 1 rating ensure compliance with demanding security standards. Engineered for 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-A, 55-B, 55-C
Product Voltage:
12/24VDC
Switch Device:
SPDT
Product Category:
Electronic Access Controls
Department:
Door Hardware

SDC 55-AU – Frequently Asked Questions

1) Will the SDC 55-A electric strike drop into an existing ANSI 4-7/8 inch strike prep?
Yes. The 55-A Uniflex strike fits an existing ANSI 4-7/8 inch strike preparation with no centerline relocation, so on a hollow metal frame already cut for a standard ANSI strike you are replacing the strike, not re-cutting the jamb. Run the wire, mount the body, and the interchangeable faceplate covers the opening.
2) Will an SDC Uniflex 55 strike work with my cylindrical lockset, or do I need a mortise version?
One strike covers both. The Uniflex 55-A accepts 3/4 inch throw latchbolts and deadbolts up to 1 inch throw, which puts cylindrical locksets, mortise locksets with or without a deadbolt, and mortise exit devices all in range. Measure the throw of the latch you have; if it is 3/4 inch or under and any deadbolt is 1 inch or under, the keeper takes it.
3) Can the SDC 55 electric strike be set fail-safe for a stair or egress door after it is already installed?
Fail-safe and fail-secure are field reversible on the 55 Uniflex strike, so the same part number handles both. Set it fail-safe and the keeper releases when power drops (the door unlocks on a fire alarm or power loss); set it fail-secure and it stays locked with no power. No different hardware, no return, and the setting can be flipped later if the door's role in the building changes.
4) Is the SDC 55 electric strike fire rated and Grade 1?
UL 10C fire rated, UL 1034 listed for burglary-resistant electric locking mechanisms, and ANSI/BHMA A156.31 Grade 1. Those three together are what most institutional specs ask for on a rated opening, and the Grade 1 line is usually the one on the drawing.
5) My latch is only 5/8 inch throw. Do I still need a 3/4 inch strike like the SDC 55?
A 3/4 inch keeper accepts a shorter latch, so the 55 Uniflex works, but you are paying for range you may not use. If the opening is a straight 5/8 inch cylindrical latch, the Adams Rite 7240 is a fire-rated strike built around 5/8 inch latchbolt projection, and the Hager 2925 is a 5/8 inch strike with the same field reversible fail-safe/fail-secure setup. Go to the 55 when the door has a 3/4 inch latch, a deadbolt up to 1 inch, or you want one strike to cover a mixed fleet of cylindrical and mortise openings.
6) I have a pair of doors with surface vertical rods. Will an SDC 55 strike work there?
Not the right tool. The 55 Uniflex takes a latchbolt or deadbolt into an ANSI 4-7/8 inch jamb prep, which is a single-door application. For surface vertical rod devices on a pair, the HES Folger Adam 310-4-2 is a complete electric strike pac built for surface vertical rods, and Rockwood offers a double door electric strike with a 3/4 keeper if you want to stay at 3/4 inch throw across the job.
7) The frame is an aluminum storefront jamb, not hollow metal - what electric strike should be used instead of the SDC 55-A?
The SDC 55-A is specified for hollow metal frames and fits ANSI 4-7/8 inch strike preparation. For an aluminum jamb, the Adams Rite 7100 Series is made for aluminum jambs with a flat 1-1/4 inch by 4-7/8 inch faceplate, and the Adams Rite 7160 is also an aluminum jamb strike with a 1-1/4 inch by 4-7/8 inch faceplate. Adams Rite's 7170 covers hollow metal and wood jambs with the same 1-1/4 inch by 4-7/8 inch faceplate if the job mixes frame types. Note that the 7100, 7160, and 7170 are not fire rated.
8) What is a direct alternative to the SDC 55-A electric strike for a cylindrical lock on a hollow metal frame at 12/24 VDC?
The Von Duprin 4211 32D is the closest peer: it is a heavy duty Grade 1 electric strike for cylindrical locks with 12/24 VDC field-selectable voltage and a fire rating, in the 4200 Series. The SDC 55-A also runs 12/24 VDC and is built for hollow metal door frames, accepting 3/4 inch throw latchbolts. The Hager 2930 is a second route on the same opening - a fire rated Grade 1 electric strike for cylindrical and mortise locks with 12/24 VDC dual voltage and field reversible fail safe/fail secure operation, which matches the 55-A's field reversible behavior.
9) The opening is a mortise lock, not a cylindrical lockset - is the SDC 55-A still the right strike or is there a better fit?
The SDC 55-A works with mortise locksets with or without deadbolts and mortise exit devices as well as cylindrical locksets, and takes deadbolts up to 1 inch throw. If the job is purely mortise, the Von Duprin 6210 is a heavy duty Grade 1 strike built for mortise locks, 24 VDC fail-secure and UL 10C fire rated, and the Securitron MUNL Mortise UnLatch is a Grade 1 fire rated mortise strike. The Von Duprin 6400 32D is a Grade 1 modular strike that covers mortise or cylindrical locks in fail-secure form with a 3-hour UL 10C rating.
10) Which electric strikes carry a Grade 1 rating and a fire rating for a labeled cross-corridor or stairwell door?
The SDC 55-A is ANSI/BHMA A156.31 Grade 1 and UL 10C fire rated, with UL 1034 burglary-resistant listing. Peers holding both Grade 1 and a fire rating include the Von Duprin 4211 32D, the Von Duprin 6210, the Von Duprin 6400 32D with a 3-hour UL 10C rating in fail-secure, the Securitron MUNL, the Rockwood 310-1 Series double door strike, and the HES Folger Adam 310-1(X). The Camden CX-ED1410/CX-ED1420 universal series is Grade 1 ANSI fire rated as well. The Alarm Controls AES-100 is a Grade 1 heavy duty strike.
11) Can the SDC 55-A be used on an exterior gate or a surface vertical rod exit device?
The SDC 55-A is a hollow metal frame strike for cylindrical locksets, mortise locksets, and mortise exit devices - it is not a gate or vertical rod device. For an exterior gate, the Camden CX-ED1959 Series is an outdoor rated electric gate strike, though it is not fire rated. For surface vertical rods, the HES Folger Adam 310-4-2 is a complete Grade 1 electric strike pac built for surface vertical rod applications and is not fire rated. The Locknetics NC450 is a no cut strike where the frame cannot be cut for a new prep.
12) My power supply is AC, not 12/24 VDC - which electric strikes accept AC input?
The SDC 55-A runs 12/24 VDC with field selectable dual voltage. If the transformer on the job is AC, the Trine 004 accepts 8-16VAC in a fail-secure configuration with a 6-1/4 inch by 1-3/8 inch faceplate, and the Trine 2001 accepts 16-24VAC/DC, fail-secure, with a 5-7/8 inch by 1-1/4 inch faceplate. Both of those Trine units are fire rated. A DC-only alternative in the same voltage window as the 55-A is the Dortronics 3300 Series at 12/24VDC.
13) Is the SDC 55-A strike 12 volt or 24 volt?
Both. The 55-A is field selectable dual voltage, 12/24 VDC, so it runs off whatever DC supply the access control panel already has and there is no voltage to specify when ordering. It also carries voltage and current spike protection, which matters when the strike shares a supply with maglocks or other inductive loads.
14) Do I need to specify handing on the SDC Uniflex 55 electric strike?
No handing to specify. The 55 Uniflex is a non-handed strike, so one part covers left and right hand openings, and it has horizontal alignment adjustment built in for dialing the keeper to the latch after the frame is cut. For a facility standardizing across many doors, that means one line item instead of a left and a right.
15) What do the LBM and LBMLCM options on the SDC 55 strike actually monitor?
They are the monitoring you add at order time. LBM gives latch status only, telling the panel whether the latchbolt is seated. LBMLCM adds keeper deadlocked status on top of that, so the head end knows both that the latch is in and that the keeper is locked against it. Order with no device option if the panel does not need feedback. Switching is SPDT, so it can drive either a normally open or normally closed input.
16) Is the SDC 55 electric strike rated for a high traffic door like a school or hospital corridor?
Rated for 1,000,000 endurance cycles, 2,500 lbs holding force, and 70 ft-lbs dynamic strength. That is the duty level you want on a main entrance, corridor, or tenant door that gets hit hundreds of times a day, and the dynamic strength figure is the one that speaks to someone shouldering the door rather than just pulling on it.
17) I need latch monitoring on the strike - what are the options besides the SDC 55-A?
The SDC 55-A can be ordered with LBM latch status monitoring or LBMLCM latch and keeper deadlocked status, and carries an SPDT switch device. Among peers, the Dortronics 3300 Series includes a latch bolt sensing switch at 12/24VDC on an ANSI prep strike plate of 4-7/8 inch by 1-1/4 inch, the Camden CX-ED1799L-8 is a dual monitor Grade 1 fire rated strike supplied with 8 faceplates, and the Hager 2945 rim exit strike includes a latchbolt monitor.
18) Is there a lighter duty or simpler electric strike than the SDC 55-A for a low traffic interior door?
The SDC 55-A is a commercial heavy-duty unit rated for 1,000,000 endurance cycles with 2,500 lbs holding force and 70 ft-lbs dynamic strength. Where that is more than the opening needs, the Trine 001 Series is a light commercial fail-secure strike with a 5-7/8 inch by 1-1/4 inch faceplate, and the RCI 15BS is an economy fail-secure strike for special offset latch entry. Both are non fire rated, so neither belongs on a labeled opening where the 55-A's UL 10C fire rating is required.
19) What looks like a substitute for the SDC 55-A but is not a complete strike?
The HES 1500 and HES 1600 accessory items are Grade 1 fire rated 1500 Series and 1600 Series electric strike accessories, not standalone strikes, and the HES Folger Adam 310-1(X) is a strike body for 1/2, 5/8, or 3/4 inch throw latchbolts. A complete assembly by contrast is something like the HES Folger Adam 310-4-2 electric strike pac. The SDC 55-A itself is a complete strike with an internally mounted solenoid and pigtail connectors, offered in 55-A, 55-B, and 55-C models.
20) I need to match the existing strike finish on a building standardized in satin stainless - what are the SDC 55-A and its peers offered in?
The SDC 55-A comes in 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, so a satin stainless building standard is covered by the 630. Peers already specified in that family include the Von Duprin 4211 32D, the Von Duprin 6400 32D in satin stainless steel, the Locknetics CS450-32D, the Locknetics MDS100 US32D heavy duty strike, the Locknetics MS100 US32D, and the Locknetics NC450 US32D.
21) Which heavy duty electric strikes are alternatives to the SDC 55-A for a high traffic commercial entrance?
The SDC 55-A is a commercial strike rated for 1,000,000 endurance cycles with 2,500 lbs holding force and 70 ft-lbs dynamic strength, built with stainless steel components and a heavy cast housing. Peers also classified heavy duty are the Alarm Controls AES-100 Grade 1 strike, the Locknetics MDS100 US32D, the Locknetics MS100 US32D, the Von Duprin 4211 32D, the Von Duprin 6210, and the Von Duprin 6400 32D, the last three of which are Grade 1 and fire rated.
22) Can I get the SDC 55 strike in a brass or bronze finish to match the rest of my door hardware?
Nine 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. Every one of those can be had with no monitoring, with LBM latch status, or with LBMLCM latch and keeper deadlocked status. The faceplate is stainless with square corners, so on a square-cut ANSI prep there is no filing to fit.
23) Is the solenoid on the SDC 55 strike exposed, and how does it wire in?
The solenoid is mounted internally on the 55 Uniflex, inside the cast housing rather than hanging outside it, and the unit comes with pigtail connectors for the wire run. Splice the pigtails to your 12 or 24 VDC feed in the jamb; the SPDT monitoring contacts on the LBM and LBMLCM versions land separately to the panel input.
How fast can I get the SDC 55-AU delivered?
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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-AU come with a warranty?
Absolutely. The SDC 55-AU 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-AU?
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