The PerfeX short neck thumb release features a no look open hook design, interchangeable 3 or 4 finger extensions and an integrated lanyard boos. The articulating finger extensions have a 35 degree range of motion. The PerfeX knob system provides infinite adjustability. Includes interchangeable 3 and 4 finger extensions, 3 trigger post lengths: 7/8”, 1” and 1 1/8”, small knob and trainer Lok pin. .