SK4510 vs. SK4510S SFIC: Key Override, Reversible Latch, and Push-Paddle Differences

The verified dividing line between EASILOK SK4510 and SK4510S(sfic) is the key-override path. SK4510 is a cylinder-free mechanical keypad deadlatch, while SK4510S(sfic) adds an SFIC key override that must match the facility's core and key system. Both remain candidates—not confirmed replacements—until the lock body, backset, door thickness, faceplate, holes, latch, strike, frame, paddle, and exact SKU have been verified.

SK4510 vs SK4510S at a Glance

This table separates confirmed product facts from field-fit decisions. It does not establish that every 4510- or MS4510S-style opening accepts one of these locks, and it does not establish that every feature explicitly documented for SK4510S is absent from SK4510.

What the Two Models Have in Common

Both products are mechanical keypad storefront deadlatches for compatible narrow-stile commercial-door applications. They are not residential bored locks, bottom-rail locks, or storefront deadlocks with a hookbolt or straight bolt.

Each model provides normal keypad operation without batteries, wiring, or an app. Each also uses an inside push paddle as the exit-side operating path. The confirmed SK4510 inside exit push paddle lets an occupant retract the deadlatch through the paddle configuration supplied for that model. SK4510S also has a push paddle, with current catalog information explicitly describing it as non-handed.

These shared characteristics do not establish shared field fit. Two doors can look identical from outside while using different bodies, backsets, faceplates, hole patterns, strikes, or frame preparations. Start by identifying the existing hardware, not by choosing a finish or assuming that a similar keypad shape indicates compatibility.

Use the storefront lock identification guide to confirm the deadlatch category, then use the lock-body-first selection guide to keep the SK4510 family separate from the deadlock and bottom-rail paths.

The Verified Core Difference: SFIC Key Override

SK4510 is the no-cylinder option in this comparison. It is the product direction for mechanical keypad access when a physical-key cylinder is not required in the selected lock configuration.

An SK4510S SFIC deadlatch lock adds a physical-key override path based on an SFIC, or Small Format Interchangeable Core. This may be relevant when an authorized manager, locksmith, or facility team needs a controlled key option in addition to keypad access. The current formal model name is EASILOK SK4510S SFIC.

The letters “SFIC” do not mean that every interchangeable core or existing master-key system will fit. Before selecting SK4510S, verify:

• the required core format;
• the facility keyway;
• the applicable pin count;
• the authorized facility keying and control-key arrangement;
• whether the exact SKU and order include a core, operating keys, control key, none of these, or another package configuration; and
• who is authorized to specify, supply, and service the key system.

Do not infer core compatibility from the appearance of the cylinder opening. Do not assume that a core from another lock will work merely because it is called interchangeable. Key-system review should be completed by authorized personnel without publishing bitting, decoding, bypass, or unauthorized core-removal information.

If the opening does not require a physical-key path, SK4510 may be the simpler candidate. If it requires an SFIC override, consider SK4510S only after both physical lock fit and the SFIC system have been verified.

Reversible Latchbolt and Non-Handed Paddle Are Different Concepts

Current SK4510S information confirms two separate features: an SK4510S reversible latchbolt and an SK4510S non-handed push paddle. These terms are not synonyms.

A reversible latchbolt refers to the latch component and how it can be oriented for the applicable opening. This is why SK4510S may appear in searches for a reversible latch storefront lock. The feature can reduce configuration limits, but the latch still must face the correct direction and engage the strike properly.

A non-handed push paddle refers to the interior operating component. It describes the paddle's configuration, not the entire door, lock body, latch, or frame preparation. Door swing, handing, latch orientation, lock position, strike relationship, and installation arrangement still have to be identified.

The responsible comparison is therefore:

• SK4510S has documented reversible-latchbolt and non-handed-paddle features.
• SK4510 has a documented inside exit push paddle.
• Current evidence does not support turning the two SK4510S descriptions into features proven absent from SK4510.
• Door handing and installation orientation must still be checked for either model.

Can SK4510S Replace an Existing MS4510S-Style Lock?

A search for an Adams Rite MS4510S replacement or an MS4510S keyless deadlatch should begin a compatibility review, not end it. EASILOK catalog information identifies SK4510S as a direction for compatible MS4510S-style deadlatch applications, but a name match cannot confirm the opening.

Document the existing installation from outside, inside, and the door edge. Include clear photographs of the exterior trim or cylinder area, interior paddle, faceplate, latchbolt, strike, surrounding frame, readable markings, and existing holes. Measure the exact backset from the correct references and record structural door thickness separately.

This matters especially when an existing 4510-family opening uses a 7/8-inch backset. Adams Rite documents a 7/8-inch option for the 4510 family, while current EASILOK catalog directions reviewed for SK4510 and SK4510S list 31/32, 1-1/8, and 1-1/2 inches. Never relabel 7/8 inch as 31/32 inch or treat it as close enough.

Also compare the lock-body space, faceplate, latch position, strike geometry, frame clearance, push-paddle arrangement, and hole pattern. A matching model-family name or backset alone cannot confirm an Adams Rite MS4510S replacement.

How to Check SK4510S SFIC Compatibility

SK4510S SFIC compatibility has two independent layers.

The first is mechanical fit. Confirm the lock category, body envelope, exact backset, door thickness, faceplate, holes, latch position, push-paddle arrangement, strike, frame condition, and handing record. If one critical item is unknown, the mechanical fit remains unknown.

The second is key-system fit. Confirm the SFIC core format, keyway, pin count, authorized facility keying, control-key arrangement, supplier, and exact order contents. A mechanically compatible lock can still be unsuitable for the facility's key system. A compatible core cannot compensate for an incompatible door preparation.

Use one of three statuses for each item:

• Confirmed: Supported by a measurement, clear photograph, current document, or authorized key-system record.
• Not matched: The field condition differs from the selected configuration.
• Unknown: Evidence is missing, unclear, or contradictory.

Do not convert “unknown” into “confirmed” to complete an order.

Will SK4510S Fit My Storefront Door?

The practical answer to will SK4510S fit my storefront door depends on more than the model name. SK4510S may be a candidate when the old device is the correct storefront deadlatch type, the dimensions and preparation match, an inside push paddle is appropriate, and a verified SFIC key override is required.

Check these items in order:

1. Lock category: Confirm that the existing device is a storefront deadlatch, not a deadlock, hookbolt, straight bolt, or bottom-rail lock.
2. Existing body and preparation: Compare the lock-body opening, faceplate, hole pattern, fasteners, and trim footprints.
3. Exact backset: Measure from the correct door-edge reference to the applicable operating centerline. Do not estimate from a photograph.
4. Door thickness: Record structural thickness separately from backset and compare it with the current configuration.
5. Latch and handing: Confirm door swing, handing, required latch orientation, and full strike engagement.
6. Inside exit hardware: Confirm paddle location, clearance, operation, and relationship to the existing preparation.
7. Strike and frame: Check alignment, depth, condition, and clearance. A damaged or misaligned frame can prevent proper operation even when the body fits.
8. SFIC system: Verify core format, keyway, pin count, facility keying, control-key arrangement, and package contents.
9. Exact SKU: Confirm backset, finish, included components, and current documentation for the item being ordered.

A drill-free installation should be described only after the existing preparation and selected configuration have been shown to match. If new holes, frame work, faceplate changes, strike modification, or unverified adaptation is required, the opening is not a confirmed drill-free replacement.

Which Model Should You Consider?

Consider SK4510 when all of the following are true:

• the opening requires a compatible mechanical keypad deadlatch;
• a physical-key cylinder is not required;
• body, backset, door thickness, paddle, holes, strike, and frame have been verified; and
• the exact SK4510 configuration matches the documented opening.

Consider SK4510S(sfic) when all of the following are true:

• the opening requires a compatible mechanical keypad deadlatch;
• an authorized physical-key override is required;
• the facility has confirmed the applicable SFIC core and key system;
• complete physical fit has been verified separately; and
• the exact SK4510S configuration and included components have been confirmed.

Do not choose SK4510S solely because “S” appears in an old model marking, because a page uses replacement language, or because a reversible latchbolt sounds universal. Do not choose SK4510 to avoid checking handing or preparation. The key-override requirement can select a product direction; it cannot approve the installation.

What This Comparison Does Not Prove

This page does not prove that:

• either model fits every Adams Rite, aluminum, or glass storefront door;
• every 4510- or MS4510S-style preparation is drill-free;
• SK4510 lacks a reversible latch or non-handed-paddle capability;
• a non-handed paddle eliminates door-handing review;
• any SFIC core or master-key system will work;
• a core, operating keys, or control key is included in every SK4510S order;
• 31/32 inch can replace a 7/8-inch backset; or
• one installation time or skill level applies to every opening.

Frequently Asked Questions

What is the difference between SK4510 and SK4510S SFIC?

The verified dividing line is the key-override path. SK4510 is the cylinder-free mechanical-keypad version, while SK4510S(sfic) adds an SFIC key override that must match the facility's core and key system. SK4510S documentation also confirms a reversible latchbolt and a non-handed push paddle, but current records do not prove that SK4510 lacks comparable handing features. Fit must still be checked separately.

Does a non-handed push paddle mean door handing does not need to be checked?

No. “Non-handed” describes the paddle's configuration, not the entire opening. You still need to identify the door swing and handing, confirm latch orientation, and verify that the lock body, backset, faceplate, existing holes, strike, frame, and door thickness match. A non-handed push paddle can simplify one component; it cannot turn an unverified opening into a confirmed fit.

Sources and Verification

• Current EASILOK SK4510 product listing
• Current EASILOK SK4510S(sfic) product listing
• Adams Rite 4510 Standard Duty Deadlatch
• BEST Standard Cores and Keys
• EASILOK storefront lock selection guide
• EASILOK storefront lock identification guide

EASILOK product information was used for current model and catalog directions. Absolute compatibility, universal-handing, fixed installation-time, universal-SFIC, and unconditional no-drill claims were not adopted. Adams Rite information is used to identify the reference family, 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 10, 2026.

Choose the Access Path, Then Verify the Opening

First decide whether a verified SFIC key override is required. Then complete the same lock-body and door-fit review for the selected model. If the opening, exact SKU, or key-system record remains unclear, send EASILOK support the full evidence set or ask a qualified locksmith, door professional, or authorized key-system provider to review it.