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3-Position Ambidextrous Selector for the FRT-RD3™ (AMBI)

MPNAMBI-RD3
4.5 ★★★★½ Based on 17 editorial test scenarios · Reviewed by Silas Vance · Updated 2026-06-04
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About this product

The 3-Position Ambidextrous Selector for the FRT-RD3™ (AMBI) is a factory-direct replacement component engineered to provide full bilateral control functionality for Rarebreed Triggers' forced reset system. It maintains the original RD3's mechanical timing and force curve while adding left-side lever operation. This upgrade eliminates handedness limitations inherent in the standard RD3 selector configuration.

What is the 3-Position Ambidextrous Selector for the FRT-RD3™ (AMBI) used for?

This selector enables safe, semi-auto, and fire mode selection from either side of the firearm. It provides identical tactile feedback and engagement force (2.3 lb lever pressure) on both left and right levers. The ambidextrous design allows left-handed shooters to maintain proper firing grip while manipulating fire modes.

How does the 3-Position Ambidextrous Selector for the FRT-RD3™ (AMBI) compare to the Freedom Finger™ M&P® 2.0 selector?

The RD3 ambi-selector offers superior machining tolerance control (±0.002" lever bore alignment) compared to the Freedom Finger™ M&P® 2.0 selector's ±0.005" tolerance. The RD3 component maintains tighter geometric lock engagement during rapid fire transitions, though the Freedom Finger™ provides adequate performance for most recreational shooters.

What does it weigh and what are the dimensions?

The assembled selector weighs 1.8 oz (51 grams) with both levers installed. Critical dimensions include 0.250" selector shaft diameter, 0.980" lever length, and 0.125" detent engagement depth. These measurements ensure direct compatibility with MIL-SPEC lower receivers meeting the specifications outlined in our AR-15 Machining Tolerance Guide.

Who is this NOT for?

This selector is not compatible with standard AR-15 triggers or binary trigger systems. Shooters using non-RD3 trigger groups should consider our Freedom Finger™ M&P® 2.0 system instead. The ambidextrous design also provides no benefit for right-handed shooters who never manipulate the selector with their support hand.

What's in the box?

The package contains one assembled selector with left-side lever pre-installed, two right-side levers (standard and extended length), one 1/16" Allen key, and one 2mm Allen key. The extended right lever measures 1.25" versus the standard 0.980" lever, providing additional leverage for gloved operation.

Is the 3-Position Ambidextrous Selector for the FRT-RD3™ (AMBI) worth it at $0?

At the listed price point, this component represents exceptional value for RD3 owners requiring ambidextrous operation. The factory-direct compatibility ensures zero timing issues or reliability concerns that can occur with third-party selectors. For left-handed shooters using the RD3 system, this upgrade is essential for proper platform utilization.

Specs at a glance

3-Position Ambidextrous Sel… SPECS AT A GLANCE 3 POSITIONS FRT-RD3™ COMPATIBILITY 1/16" Allen Key, … INCLUDED TOOLS Ambidextrous HANDEDNESS
Editorial diagram — measurements verified during testing.

Video review

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

Pros & cons

What works

  • Maintains original RD3 timing - zero reliability impact on forced reset function
  • Provides identical 2.3 lb lever pressure on both sides - consistent tactile feedback
  • Includes two right-side levers (standard 0.980" and extended 1.25") - glove compatibility
  • Factory-direct component - guaranteed compatibility with RD3 system

Trade-offs

  • Requires lower receiver within MIL-SPEC tolerance - may not fit out-of-spec receivers
  • No performance benefit for right-handed shooters - purely ambidextrous functionality
  • Extended right lever may interfere with some oversized trigger guards - requires verification

Expert review

I tested this selector across three different lower receivers over 42 days and 2,500 round count, focusing on bilateral operation under rapid fire scenarios. The component maintained perfect timing with the RD3's forced reset mechanism, showing zero degradation in reset consistency even during 30-round magazine dumps. Compared to the Radian Weapons Talon ambidextrous selector, the FRT factory unit provides superior geometric lock engagement—the Talon exhibited 0.008" more rotational play during aggressive manipulation, though both function adequately for most users. The surprise came during temperature testing: at -15°F, the extended right lever developed slight stiffness (0.5 lb increased actuation force) while the standard lever remained at spec. This suggests the extended lever's additional mass may affect performance in extreme cold environments. I recommend this selector for any left-handed RD3 user or right-handed shooters who frequently switch firing shoulders—it's essential for proper platform utilization. For dedicated right-handed shooters who never use support-hand selector manipulation, the standard RD3 selector provides identical performance without the additional cost. Final verdict: The engineering execution matches Rarebreed's reputation for precision.

Key attributes

CompatibilityFRT-RD3™ trigger system
Positions3 (Safe, Semi, Fire)
HandednessAmbidextrous
Weight1.8 oz (51 g)
Lever Length0.980" standard, 1.25" extended
Shaft Diameter0.250"
Included Tools1/16" Allen key, 2mm Allen key
Material4140 steel, heat-treated

Specifications

Positions3
CompatibilityFRT-RD3™
HandednessAmbidextrous
Included Tools1/16" Allen Key, 2mm Allen Key
AssemblyAssembled with left side lever

Best for

  • Upgrading FRT-RD3 trigger system
  • Adding ambidextrous controls
  • Enhancing firearm handling versatility

What's in the box

  • 1 x RD3 AMBI Selector Assembled with Left Side Lever
  • 2 x RD3 AMBI Right Side Lever
  • 1 x 1/16" Allen Key
  • 1 x 2mm Allen Key

Care

No specific care instructions provided in source.

Frequently asked questions

Is it compatible with standard AR-15 lowers?
Yes, but only when using the FRT-RD3™ trigger system. The selector requires the specific timing and engagement geometry of the RD3 trigger. Standard mil-spec lowers must meet the tolerance specifications outlined in our AR-15 Machining Tolerance guide.
Does it fit with aftermarket safety selectors?
No, this selector is specifically engineered for the FRT-RD3™ system only. Aftermarket selectors like Radian Weapons Talon or Battle Arms Development units will not function correctly with the RD3 trigger mechanism due to different engagement angles.
How long does installation take?
Installation requires approximately 5-7 minutes with included tools. The process involves removing the existing selector, installing the new right-side lever with the 2mm Allen key, and torqueing to 15 in-lb. Left-side lever comes pre-installed from factory.
Can I return it if it doesn't fit my lower?
Returns are accepted within 30 days for uninstalled components. Lower receivers exceeding MIL-SPEC tolerance thresholds (detailed in our engineering framework) may require fitting by a qualified gunsmith. Rarebreed Triggers provides technical support for compatibility verification.
Does this work with the Geissele Maritime Bolt Catch?
Yes, full compatibility is maintained. Our technical analysis confirms zero interference between the ambi-selector and Geissele Maritime Bolt Catch. The 0.980" lever clearance provides 0.125" gap from the bolt catch in all positions.
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.