SideStix grip covers are made from SPENCO neoprene and covered with four-way stretch nylon. These light-weight, washable covers provide excellent cushioning. They are hand stitched by Salt Spring Footprints, manufacturers of custom orthotics and are compatible with Ergon grips. The grip cover size should match your grip size. Please call or email us if you are unsure which grip size you have. Generally, if the distance from tip of pinky to tip of thumb is greater than 8”, then you should be using large grips.