STAN OnneX Heavy Metal Thumb ReleaseThe OnneX Thumb is built off the culmination of all the thumb releases that STAN has ever made to give the best and fastest firing mechanism we have ever engineered. Resulting in zero trigger travel and great adjustability for trigger tension from a hair trigger to extremely heavy. Zero trigger travel and great adjustability for trigger tension from a hair trigger to extremely heavy. INCLUDED IN THE PACKAGE: Interchangeable 3 or 4 finger pieces 2