Seamlessly attach your Beeline Velo 2 to your bike. Compatible with all standard stem mounts. What’s in the box: stem cap base, stem cap bolt, mount adapter insert, and mount adapter insert screws x 2. The Beeline Velo 2 stem cap mount is designed to replace a stem cap on a typical threadless stem. The stem cap is the small, circular cap at the top of your bike’s headtube. Threadless stems are found on the vast majority of modern bikes. This mount will not work with threaded stem caps.