AIM7 Booster Assembly & Piston – 1-3/8x24 T– 17-4 Stainless Steel Nielsen type

AIM7 Nielsen-Type Booster Assembly with Piston – 1-3/8x24 Thread. TheAIM7 Booster Assembly is a precision-engineered mounting system designed to replace standard direct-thread adapters for users needing aNielsen-type recoil booster system.