Make sure you read the bolded note at the bottom.
From the manufacturer
Battle Arms Development - Ambidextrous Safety Selector (BAD-ASS) for the AR15 Style Rifles and the ArmaLite, Inc.'s AR10® (Semi Auto). The Levers are detachable and interchangeable on both sides for maximum flexibility and user preference. The BAD-ASS is a must have for the "South Paw" and Ambidextrous Shooters!
Each Retail Package Comes With:
- (1) REVERSIBLE SAFETY CENTER (0°-50° and 0°-90° SEMI AUTO)
- (2) LEVERS - BLACK PHOSPHATE
- (2) TORX SCREWS BLACK OXIDE
- (1) HARDENED STAINLESS STEEL SAFETY DETENT (by KNS Precision)
- (1) T10 TORX L-Key
- (1) SELECTOR DETENT SPRING
- PRECISION CNC MACHINED FROM BAR STOCK STEEL
- MADE IN U.S.A.
- PATENT NO.: US 8,806,790 B1, OTHER PATENTS PENDING
ArmaLite and AR-10 are registered trademarks of ArmaLite, Inc.
- Torx screw torque value should be approximately 5 In-Lbs. Do not over tighten.
- Some fitting may be required with Geissele Triggers on the 50° Short-Throw side.
- BAD-ASS-ST Short Throw Safety Selector will not fit in "standard" AR-style lower receivers designed for 0°-90° throw safety selectors. A relief cut on the left side of the receiver safety selector hole is required to allow the safety pin block device on the BAD-ASS-ST center to pass through. The safety pin block is there for your safety so it cannot be installed on a "standard" AR and allow the safety selector lever to point ambigously between SAFE and FIRE. "Short-Throw" compatible lower receivers with safety pin relief cut and 45° to 90° FIRE marking (such as the BAD-15 Forged Lower and BAD556-LW Lower Receivers) are required for proper installation. Any modification to the safety selector will render the warranty null and void.