The Allen Company Titan SlideGuide Crossbow Sled is engineered to fit many crossbow rail designs, so you are not limited to a single-sized width. The rail's groove will keep the sled aligned as you pull the sled up, and the self-aligning guide spring system runs along the side of the crossbow rails, keeping the sled perfectly aligned during movement. These two physical features work in tandem to keep your sled balanced and in perfect contact with the crossbow, making cocking easy.