This is the Atrius Ambidextrous X-SERIES Forced Reset Selector. It's the latest addition to the FRS family which features a new trip system that has a slip base and slip clutch to allow for a universal fitment amongst gas piston platforms.
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The Atrius Development Group FRS X-Series was designed to be compatible with a variety of Sig Sauer MCX®, MPX®, Rattler® platforms, and even Sig's MCX-Spear LT Upper AR Conversion Kit.
Includes a new FRS lever with dimension compatible for MCX/MPX product lines
Universal design for Sig Sauer® gas piston platforms
Installation: Drop-In Ready (No Modifications Necessary)
Manufactured in the USA
Materials
Corrosion Resistant Black Nitride Finish
Made of Heat Treated 4140 Steel
Compatibility
Platform Compatibility: MCX®, MCX-Spear LT®, MCX-Rattler LT®, MCX-Spear LT Upper AR Conversion Kit®, MPX PCC®, MPX-K®. Compatible with all generations (safety latch may need to be removed in early gens).
Trigger Compatibility: Mil-Spec Triggers that come with MCX/MPX platforms. Single stage mil-spec triggers that do not have a u-notch or relief cut.
Drop-In Installation
Swap out your factory safety in minutes and experience the next level of firearm ownership.
Runs with Mil-Spec Fire Control Groups
Seamlessly integrates with standard AR fire control groups and some cassette style triggers.
Hardcore Durability
Crafted from heat-treated, 4140 steel and coated in a corrosion-resistant black nitride finish. Rain, mud, sweat—it eats it all for breakfast.
No Modifications Necessary
No cutting your triggers. Ensures flawless function and longevity without modification.
Aggressive Ergonomics
Textured, chamfered-edge, and purpose-built design for speed. Your fingers will find the selector instantly, even under stress.
Installation Steps for X-Series Ambidextrous Forced Reset Selector
1Install X-Series FRS as you normally would any other safety selector.
2Install your fire control group (trigger).
3Insert trip base on left side of the receiver and marry to rear trigger pin.
4Insert trip clutch onto the track of trip base and push all the way forward.
5Press trip base down so it's under rear takedown pin.
6Ensure the entire trip hasn't shifted during previous steps.
7Install upper receiver and dry function check.
Atrius Forced Reset Selectors
Product Comparison
Product
Single Switch
Ambi Switch
Lever Blocker
For Gas Piston System
Notes
FRS Standard / Single
✓ Yes
—
—
—
Standard ergonomic switch for ease of use
FRS Mil-Spec / Single
✓ Yes
—
—
—
Has mil-spec style switch
FRS Ambi
—
✓ Yes
—
—
Great for left-handed users
FRS Ambi G-Lever
—
✓ Yes
✓ Yes
—
Has additional Geissele trigger compatibility
FRS Ambi X-Series
—
✓ Yes
—
✓ Yes
Compatibility
All Atrius FRS products have direct compatibility with mil-spec triggers that do not have a relief cut (U-notch).
They also are compatible with a wide variety of single-stage, drop-in / cassette style triggers as well.
The “G-LEVER” is the only FRS product that carries expanded compatibility to work with select Geissele triggers and similar products that feature a reduced hammer design.
Compatible with all generations (safety latch may need to be removed in early gens)
Compatibility Note
The FRS is drop-in compatible designed with mil-spec and full profile AR15 components. Check out our compatibility page for more information.
Military-grade steel construction for maximum durability
Positive Positioning Detent
Precise 90° indexing with tactile feedback
Restricted States
This product cannot be shipped to the following states:
California
Connecticut
Colorado
Delaware
District of Columbia
Florida
Hawaii
Illinois
Maryland
Massachusetts
Minnesota
Nevada
New Jersey
New York
Oregon
Rhode Island
Virginia
Washington
US Territories
International
Legal Compliance
By purchasing this product, you acknowledge that you are legally permitted to own and possess it in your jurisdiction. It is your responsibility to ensure compliance with all federal, state, and local laws. The Atrius FRS is designed as a safety selector and must be used in accordance with all applicable firearms regulations. We are not responsible for misuse or violations of law.
Important Notice
This product is intended for lawful use only. Purchaser assumes all responsibility for legal compliance in their jurisdiction.