The CCM custom IVG allows you to adjust hammer spring pressure without having to take your cocking rod out of your hammer. The CCM IVG has three hex wrench adjustment holes around the face of the IVG. Once your back block is in the back position insert the 1/8 allen wrench (which is included) and turn clockwise for more spring pressure and counter clockwise for less. CCM products carry a LifeTime Workmanship Warranty. This warranty applies only to the original purchaser and is NON-TRANSFERABLE. This warranty does not apply to items that have been abused, misused, modified or repaired.