Kegel Wheel Pulley Mod for Boosted Board V1 Electric Skateboard. Material: 3D printed (solid) nylon for high wear resistance Includes: 2 pulleys Purpose: Our pulleys allow you to swap larger wheels where you can get a more comfortable ride and also more top speed (depending on how big the wheel is… bigger wheel = more top speed) Fits perfectly. Comes with 30 day anything happens I will replace it warranty.