SK1850 vs. SK1850S SFIC: Which Keyless Storefront Deadlock Should You Choose?
Choose EASILOK SK1850 when you want mechanical keypad access without a physical-key cylinder. Choose SK1850S(sfic) when you also need a separately verified SFIC key-override path. Both remain candidates only after the existing lock body, exact backset, door thickness, bolt, holes, frame or receiver, and current configuration have been checked.
peiSK1850 vs. SK1850S at a Glance
| Decision point | SK1850 | SK1850S(sfic) |
|---|---|---|
| Main access method | Mechanical keypad | Mechanical keypad |
| Physical-key cylinder | None | SFIC configuration; verify the exact core and SKU |
| Key-override path | No | Yes, after the SFIC configuration is confirmed |
| Batteries, wiring, or app | Not required for normal operation | Not required for normal operation |
| Lock-body category | Narrow-stile storefront deadlock | Narrow-stile storefront deadlock |
| Replacement direction | Compatible MS1850S-style applications | Compatible MS1850S-style applications |
| Bolt directions | Hookbolt or straight deadbolt, depending on the verified SKU and site | Hookbolt or straight deadbolt, depending on the verified SKU and site |
| Listed backset directions | 31/32, 1-1/8, or 1-1/2 inches | 31/32, 1-1/8, or 1-1/2 inches |
| Listed door-thickness direction | 1-3/8 to 1-3/4 inches | 1-3/8 to 1-3/4 inches |
| Extra verification | Complete door-and-lock fit check | Complete door-and-lock fit check plus SFIC system verification |
The first question is whether a verified physical-key override is required. The second question is whether the selected lock, bolt, backset, trim, holes, frame, receiver, and key system match the actual opening. The first answer never replaces the second.
What Both Models Share
SK1850 and SK1850S(sfic) are mechanical keypad storefront deadlocks. Normal keypad operation does not depend on batteries, wiring, electronics, Wi-Fi, or an app. Both are product directions for compatible narrow-stile storefront doors using an MS1850S-style deadlock preparation.
Current EASILOK product information lists the same general directions for both families:
- 31/32-inch, 1-1/8-inch, and 1-1/2-inch backsets;
- 1-3/8-inch to 1-3/4-inch door thickness;
- hookbolt or straight-deadbolt configurations;
- black or silver finishes; and
- a three-year mechanical warranty.
These shared fields do not prove that the two models can be exchanged at every site or that every bolt-and-backset combination is currently available. Confirm the exact SKU and compare it with the existing preparation.
Choose SK1850 When No Physical-Key Cylinder Is Needed
SK1850 is the simpler branch when the requirement is mechanical keypad access and the installation does not need a physical-key cylinder or an existing facility key system. It avoids a second cylinder-and-keying decision, but it does not eliminate the field-fit decision.
Before choosing SK1850, confirm:
- The existing hardware is a narrow-stile deadlock rather than a deadlatch or bottom-rail lock.
- The exact backset matches a current SK1850 configuration.
- Door thickness is within the verified direction.
- Hookbolt or straight-deadbolt configuration matches the door and receiver.
- Faceplate, cutout, holes, trim footprint, frame, strike or receiver, and interior operation are suitable.
Use the SK1850 compatibility guide for the full model-specific evidence checklist. If that page is not yet live, keep A06 hidden until the internal link can be tested.
Choose SK1850S When a Verified SFIC Override Is Required
SK1850S(sfic) is the relevant branch when the site needs mechanical keypad access plus a physical-key override through a verified Small Format Interchangeable Core configuration. This can be useful when a business or facility has a managed keying requirement, but “SFIC” is a core format—not a promise that any core or existing master-key system will work.
The model decision is therefore two decisions:
- Door-lock fit: Does the SK1850S lock, bolt, backset, trim, hole pattern, door, frame, and receiver match?
- Key-system fit: Does the intended core, keyway, pin count, control-key arrangement, and facility keying match the exact SK1850S configuration and order?
If either decision remains unknown, the result is not yet confirmed.
Verify the SFIC Core Separately
SFIC means Small Format Interchangeable Core. The name describes a removable core format used in certain managed key systems. BEST’s current reference shows that SFIC can involve different pin counts and multiple keyways, so the initials alone do not identify one universal core or key system.
Check all of the following:
| SFIC check | What to confirm | Why it matters |
|---|---|---|
| Exact lock and SKU | The selected SK1850S configuration is intended for the required SFIC setup | A model-family name is not enough to identify package contents or a current SKU |
| Core format | The intended cylinder is actually SFIC, not another interchangeable or conventional cylinder format | Similar-looking cylinders can use different formats |
| Pin count | The core and the intended housing/keying plan use the required pin count | SFIC is available in more than one pin-count configuration |
| Keyway | The keyway matches the authorized keys and facility standard | An SFIC-shaped core does not make different keyways interchangeable |
| Facility keying | Operating keys, control key, master-key hierarchy, and records are coordinated by the authorized key-system provider | A core can fit physically while remaining incompatible with the site’s keys or keying plan |
| Package contents | Confirm whether the exact order includes the core, operating keys, control key, or only the lock prepared for SFIC | “Supports SFIC” does not automatically mean every component is included |
Do not publish key bitting, decoding, bypass, or core-removal instructions in this comparison. Key-system configuration and service should remain with authorized personnel.
Will SK1850S Fit My Storefront Door?
SK1850S may be a candidate only when both the door-lock fit and the SFIC configuration have been verified. A similar exterior, an MS1850S reference, or one matching measurement does not establish compatibility.
| Fit check | Evidence required | Stop or escalate when |
|---|---|---|
| Existing lock body | Door-edge photo, complete faceplate, bolt, old marking when available | Existing hardware is a deadlatch, bottom-rail lock, flush bolt, or unidentified preparation |
| Backset | Ruler-based measurement with the correct start and operating-center references | Reading is unclear, 7/8 inch, or outside the current EASILOK direction |
| Door thickness | Structural face-to-face measurement | Measurement is outside the verified direction or includes unverified trim |
| Bolt and receiver | Hookbolt or straight deadbolt together with its strike, jamb opening, or receiver | Bolt type, orientation, receiver, or door movement differs |
| Cutout and holes | Faceplate, mortise area, screw positions, openings, and trim footprint | Drilling, cutting, patching, or hidden modifications may be required |
| Door and frame | Alignment, clearances, handing record, frame condition, and interior operation | Door drags, frame is damaged, strike is misaligned, or operation is abnormal |
| SFIC configuration | Core format, keyway, pin count, facility keying, and exact order contents | Any part of the key system is unknown or assumed from the SFIC label alone |
Use the storefront lock identification guide first, then record the measurements with the storefront lock measurement guide.
Fit Checks That Apply to Both Models
Whether the first branch is SK1850 or SK1850S, keep one shared evidence record:
- Existing lock-body category and old model marking.
- Exact backset with visible measurement references.
- Structural door thickness.
- Hookbolt or straight deadbolt and its receiver.
- Mortise cutout, faceplate, holes, trim footprint, and any previous modification.
- Door movement, frame or strike condition, handing record, and interior operation.
- Exact EASILOK bolt, backset, color, and current SKU being considered.
Mark each item confirmed, not matched, or unknown. An unknown item should not be converted into a match to complete an order.
Do Not Substitute 31/32 Inch for a 7/8-Inch Backset
Adams Rite’s official MS1850S reference includes a 7/8-inch backset in addition to 31/32, 1-1/8, and 1-1/2 inches. Current EASILOK SK1850 and SK1850S information lists 31/32, 1-1/8, and 1-1/2 inches, but not 7/8 inch.
If the old lock measures 7/8 inch, neither model should be presented as a confirmed candidate from the current information. Do not round the measurement, treat the two fractions as equivalent, or select 31/32 inch because it appears close.
Decision Examples
| Site requirement | Responsible result |
|---|---|
| Mechanical keypad access; no physical-key cylinder needed; all fit evidence matches | Consider the verified SK1850 configuration |
| Mechanical keypad access plus an authorized SFIC override; door fit and key-system details both match | Consider the verified SK1850S configuration |
| Site says “we use SFIC,” but keyway, pin count, control key, or current order contents are unknown | Pause the model decision and have the key-system details verified |
| Old lock has a 7/8-inch backset | Do not substitute a listed EASILOK backset; request a model-specific review |
| Existing hardware is a deadlatch with a paddle or a bottom-rail lock | Return to the correct EASILOK product family; neither SK1850 nor SK1850S is the right category |
| Door, frame, holes, bolt, or receiver is damaged or altered | Obtain a qualified field assessment before choosing either model |
What This Comparison Does Not Prove
This page does not prove that:
- either model fits every Adams Rite, Kawneer, Clark, aluminum, or glass storefront door;
- every existing MS1850S-style installation is drill-free;
- 31/32 inch can replace 7/8 inch;
- any SFIC core or master-key system will work;
- a core, operating keys, or control key is included in every SK1850S order;
- one installation time applies to every opening; or
- model selection removes the need for a locksmith or door professional when the site is damaged, modified, unclear, or subject to life-safety requirements.
Frequently Asked Questions
What is the difference between SK1850 and SK1850S SFIC?
The main decision is whether the installation needs an SFIC key-override path in addition to mechanical keypad access. SK1850 has no physical-key cylinder; SK1850S(sfic) adds an SFIC path. Both still require verification of the lock body, backset, door thickness, bolt, holes, frame, and receiver, while SK1850S also requires core-format, keyway, pin-count, facility-keying, and exact-SKU checks.
What does SFIC mean?
SFIC means Small Format Interchangeable Core, a removable core format used in certain managed key systems. It is a format name, not a universal compatibility claim. Before choosing SK1850S(sfic), verify the intended core format, pin count, keyway, facility keying, control-key arrangement, and whether the exact order includes the required core and keys.
Sources and Verification
- Current EASILOK SK1850 product listing
- Current EASILOK SK1850S(sfic) product listing
- Adams Rite MS1850S Series Deadlocks
- BEST Standard Cores and Keys
- EASILOK storefront lock identification guide
- EASILOK storefront lock measurement guide
EASILOK product pages were used for current model, option, and specification directions only. Their absolute compatibility, installation-time, universal-SFIC, and no-drill marketing statements were not adopted. Adams Rite information is used to identify reference configurations, not to assign Adams Rite specifications or certifications to EASILOK products. BEST information supports the general SFIC definition and the need to verify pin count and keyway. Last reviewed: August 4, 2026.
Choose the Access Path, Then Verify the Opening
First decide whether the site needs a verified SFIC key override. Then complete the same lock-body and door-fit check for the selected model. If the opening, current SKU, or key-system record remains unclear, send EASILOK support the full photo, measurement, bolt, frame, and keying evidence, or ask a qualified lock or door professional to review the site.