This string dampener is the one that put Bowjax on the map. It is designed to be used without a bow press. Simply put the Ultrajax I on the string and use the supplied plastic ties or your own string material to cinch string silencer to the string. The Ultrajax I system is an easy way to silence the noisy string. For crossbow users that are looking for even more dampening ability, attach a Slipjax to your cable.