CAM-LOK™ (Covert Application Mount-Locking) Patented Universal QD piston attachment system – 3 mounting positions 120 degrees separated for rapid mounting – Forward taper surface locks in place with interfacing piston and drastically reduces or eliminates common baffle/end cap strikes – Coarse threads are top cut to increase durability and wear resistance – 3/4or 19mm wrench pattern accommodates socket wrench for secure and easy installation – Compatible with Universal QD pistons (sold separately) – Internal bore reduces side concussion and visual disturbance vs blind muzzle – Total system weight is identical to legacy direct thread pistons – QPQ Nitride finish for attractive durable black finish – 17-4 stainless steel material – Also supports Universal Carry Comp