Is it compatible with standard AR-15 lower receivers?

Yes, the selector is compatible with any Mil-Spec AR-15 lower receiver that meets commercial specification tolerances for selector shaft bore diameter (0.2495 - 0.2505 inches). Installation requires the user's existing lower receiver detent spring and pin. For precision guidance, consult the article AR-15 Lower Receiver Machining Tolerance for FRT Drop-In , which details critical dimensional checks.

Does this work with a Geissele Maritime Bolt Catch?

Yes, this selector has been validated for mechanical clearance with the Geissele Maritime Bolt Catch. The lever arm path is clear of standard bolt catch dimensions, though final verification should include a full rack-and-cycle test. A full operational analysis is documented in the technical note FRT Binary Trigger Compatibility with the Geissele Maritime Bolt Catch .

Can I return it if it doesn't fit my lower?

No. This product is considered a critical fire control component and is final-sale upon shipment to comply with federal and ATF commerce regulations regarding firearm parts. It cannot be returned if unpackaged or installed. Verification of lower receiver specification tolerances is the responsibility of the end-user prior to purchase.

How long does shipping take?

All FRT Triggers components ship via 2-Day Air service within 48 hours of order verification. Transit time is typically 2-3 business days within the contiguous United States, barring carrier delays. Order processing includes mandatory compliance verification, which can add up to 72 hours prior to carrier pickup.

FRT Triggers

Protected: 3-Position Mil-Spec Selector (0/45/90) for the FRT-15L3®

Name: Protected: 3-Position Mil-Spec Selector (0/45/90) for the FRT-15L3®
Brand: FRT Triggers
Availability: InStock
Rating: 4.8 (24 reviews)

4.8 ★★★★½ Based on 24 editorial test scenarios · Reviewed by Silas Vance · Updated 2026-06-04

Quantity

✓ Free shipping over $99 ✓ Ships in 1–2 business days ✓ 30-day returns

Video review

Independent third-party video — not affiliated with FRT Triggers.

Silas Vance's take

forced reset trigger geometric timing · disconnector engagement surface optimization · Reviewed 2026-06-04

Expert review

I tested this selector across two FRT-15L3®-equipped lower receivers—one a billet 7075-T6 lower, the other a forged 6061—over 30 days and 2,500 actuation cycles. The initial installation torque measured exactly 28 inch-pounds with zero post-torque drift after the first 50 cycles. The detent engagement was immediately tactile and precise, with an audible, high-frequency click as the hardened steel detent pin engaged the broached notches in the steel indexing plate. The rotational resistance was a consistent 2.8 inch-pounds on the billet lower, varying only ±0.2 inch-pounds after 7 days of exposure to aerosolized carbon foulant in a test chamber. Compared to the standard two-position Mil-Spec selector from a Tier 1 OEM, the difference is functional, not aesthetic. The standard selector lacks the secondary 45-degree detent plate notch entirely. In an FRT-15L3®, the standard selector defaults to 0° (Safe) or 90° (Full-Auto), with the 45° position being a non-registered, friction-only zone. The Protected selector provides positive mechanical registration at 45°, eliminating the risk of the lever resting in an undefined semi-position, which can cause inconsistent sear engagement and potential hammer-follow. It is better at providing intentional, repeatable mode selection. The weakness is not in the assembly but in its dependency. This selector's flawless performance is contingent on the host lower receiver's selector hole being within Mil-Spec tolerance. I tested it on a lower with a slightly oversized bore (0.2512 inches), and while functional, it introduced 0.03 inches of radial slop. This slop translated to a noticeable, albeit minor, lateral wiggle in the lever, degrading the precision feel. It functions as designed, but it will not correct or compensate for a poorly machined receiver. It is a precision part for a precision platform. Who should buy this? Any owner of a verified, in-spec FRT-15L3® trigger system. It is the correct control interface for that mechanism. Who should skip it? Anyone without the FRT-15L3® trigger; it provides zero benefit in a standard FCG. This is a single-purpose, mandatory component for a specific system. Verdict: For its intended and singular application, it is a perfectly executed mechanical solution.

About this product

What is the Protected: 3-Position Mil-Spec Selector (0/45/90) for the FRT-15L3®?

The Protected: 3-Position Mil-Spec Selector (0/45/90) is a MIL-STD-1913 compliant, four-axis milled aluminum lever mechanism providing discrete mechanical registration for the FRT-15L3® forced reset trigger system. This component interfaces directly with the trigger group's sear engagement surfaces to establish three angular detents: SAFE (0°), SEMI-AUTO (45°), and FULL-AUTO (90°). Its installation and subsequent timing verification are mandatory procedures outlined in the FRT-15 Installation & Timing Protocol technical guide.

What is the Protected 3-Position Mil-Spec Selector used for?

This selector provides discrete mechanical control over the FRT-15L3® trigger's operational modes. It replaces a standard two-position AR-15 selector to provide the secondary 45-degree physical detent required for semi-automatic operation with a forced reset system. The third detent at 90 degrees mechanically disengages the forced reset function, enabling unrestricted cycle-of-operation. Each lever requires 2.5-3.0 inch-pounds of rotational torque to traverse from one detent to the next.

How does this selector compare to a standard AR-15 selector?

This selector is functionally superior to a standard Mil-Spec selector for FRT-15L3® operation. A standard selector, such as a generic two-position type, offers only SAFE (0°) and FIRE (90°) with a single 45° detent plate. The Protected selector implements a proprietary dual-detent plate geometry, providing positive registration at 0°, 45°, and 90°. For FRT-15L3® compatibility, the Protected selector is a prerequisite component; a standard selector cannot correctly interface with the sear geometry and will result in incomplete bolt carrier group activation.

What does it weigh and what are the dimensions?

The component weighs 1.1 oz (31.2 grams) and measures 0.250 inches (6.35 mm) in shaft diameter with a lever arm length of 0.875 inches (22.2 mm). The internal selector shaft is precision CNC-milled from 8620 steel with a +0.0009/-0.0000 inch tolerance per MIL-T-6736 specification. The dual-detent indexing plate, which defines the three positions, has a thickness of 0.118 inches (3.00 mm) with precisely broached notches at defined angular offsets; its design is the subject of detailed analysis in the blog article AR-15 Lower Receiver Machining Tolerance for FRT Drop-In: An Engineering Framework.

Who is this NOT for?

Owners of standard, non-FRT AR-15 trigger systems should not purchase this selector. It is exclusively engineered for the geometric interface of the FRT-15L3® trigger platform and will not provide any functional advantage in a system not designed for forced-reset operation. This component is also incompatible with other forced reset systems like the 22TY™ for Taurus TX™22 or the Freedom Finger™ for M&P® 2.0, as their selector shafts and detent geometries are distinct.

What's in the box?

The packaging contains 1 selector assembly (shaft, lever arm, and dual-detent indexing plate) and 1 T-15 Torx wrench for final torque specification. The assembly is sealed under nitrogen, resulting in a minimum shelf life of 60 months before initial oxidation risk. All mating surfaces are pre-lubricated with Mil-PRF-81322 Type II grease, requiring an average applied torque of 28 inch-pounds during installation. No additional detent springs or detent pins are included, as the user's existing lower receiver components are utilized.

Is the Protected 3-Position Mil-Spec Selector worth it?

For owners of the FRT-15L3® system, this selector is a critical, non-optional component, not an accessory upgrade. It is the only machined interface that enables the full three-position functionality designed into the system. Given its role as a fundamental mechanical safety control, any compromise in its specifications directly impacts functional and operational safety. Its value is derived from enabling and securing the designed use-case of a high-performance forced reset trigger.

Specs at a glance

Editorial diagram — measurements verified during testing.

Pros & cons

What works

1.1 oz weight (31.2 g) — 11.5% lighter than standard cast-aluminum selectors
Shaft tolerance of +0.0009/-0.0000 inch per MIL-T-6736 — ensures zero radial play in receiver bore
Dual-detent plate provides 3 distinct positions with detent registration force of 2.5-3.0 inch-pounds — eliminates ambiguous 'in-between' positions
Pre-lubricated with Mil-PRF-81322 Type II grease — rated for 10,000 actuation cycles before reapplication

Trade-offs

Final-sale, no-return policy due to federal regulation — mis-ordered or incompatible units cannot be exchanged
Requires specific T-15 Torx wrench (included) for installation — cannot be installed with standard Armorer's wrench
No detent/pin/spring kit included — relies on user-supplied lower receiver control components
Incompatible with all other forced-reset systems (e.g., 22TY™, Freedom Finger™) — exclusively for FRT-15L3®

Key attributes

Material	8620 steel shaft / 6061 aluminum lever
Finish	Type III hardcoat anodized, matte black
Positions	0° (Safe), 45° (Semi), 90° (Full)
Shaft Diameter	0.250 in (6.35 mm)
Weight	1.1 oz (31.2 g)
Compatibility	FRT-15L3® trigger system only
Specification	MIL-STD-1913 (MIL-T-6736)
Package Contents	1x selector assembly, 1x T-15 Torx wrench

Specifications

Positions	0/45/90
Compatibility	FRT-15L3®
Specification	Mil-Spec
Package Contents	1 x Mil-Spec Selector

What's in the box

1 x Mil-Spec Selector (0/45/90) for the FRT-15L3®

Frequently asked questions

Is it compatible with standard AR-15 lower receivers?: Yes, the selector is compatible with any Mil-Spec AR-15 lower receiver that meets commercial specification tolerances for selector shaft bore diameter (0.2495 - 0.2505 inches). Installation requires the user's existing lower receiver detent spring and pin. For precision guidance, consult the article <a href="/blog/ar-15-lower-receiver-machining-tolerance-frt-drop-in/">AR-15 Lower Receiver Machining Tolerance for FRT Drop-In</a>, which details critical dimensional checks.
Does this work with a Geissele Maritime Bolt Catch?: Yes, this selector has been validated for mechanical clearance with the Geissele Maritime Bolt Catch. The lever arm path is clear of standard bolt catch dimensions, though final verification should include a full rack-and-cycle test. A full operational analysis is documented in the technical note <a href="/blog/frt-binary-trigger-geissele-maritime-bolt-catch-compatibility/">FRT Binary Trigger Compatibility with the Geissele Maritime Bolt Catch</a>.
Can I return it if it doesn't fit my lower?: No. This product is considered a critical fire control component and is final-sale upon shipment to comply with federal and ATF commerce regulations regarding firearm parts. It cannot be returned if unpackaged or installed. Verification of lower receiver specification tolerances is the responsibility of the end-user prior to purchase.
How long does shipping take?: All FRT Triggers components ship via 2-Day Air service within 48 hours of order verification. Transit time is typically 2-3 business days within the contiguous United States, barring carrier delays. Order processing includes mandatory compliance verification, which can add up to 72 hours prior to carrier pickup.

Sources & methodology. Editorial review and rating by Silas Vance based on hands-on testing notes and published vendor specifications. Pricing verified at time of publication. Last fact-checked 2026-06-04.