Do you want to improve your guns accuracy allowing the spear shaft to smoothly leave the guns stock with less wobble and a straighter path? Tru-Glide Rail is used to assist in keeping the shaft in place without slowing down its speed. Kitis designed for the Magnum and Carbine Series Spear Guns (4D33, and D-6's) and is easy to install. So if you are looking for increased accuracy and keeping your spear shaft properly in place be sure to install the Tru-Glide Kit.