The frame and the central pin are in aisi 316 steel. The drilling on the frame itself allows it to be used also on arbalete spearguns of different brands. The special clutch provides an excellent closing torque. The assembly system allows easy maintenance and cleaning. All sizes are equipped with a rewinder ring and size r50 is also equipped with an antiblocking roller. The models r30 and r50 are equipped with a lightened drum in order to weigh as little as possible on the balance of the speargun