It wasn't good enough for us to just have a mechanical head in our line, so we reinvented the mechanical head. The EXP brings a new level of computer-controlled machine capability to broadhead building. Starting with a tiny, spring tension clip that holds the blade in place when open and closed, and ending with a new idea in stop collars that lets YOU choose from two cutting diameters just by flipping the collar. The EXP is a masterful blend of engineering and technology.