Each Lezyne GPS unit comes with a Standard GPS mount and this bracket kit is available if spares or replacements are needed. Included are two sets of o-rings (two diameters), plus a backup o-ring in each size, a rubber shim and an X-Lock composite mounting bracket. The rubber shim supports the X-Lock mount which is engineered to attach at any 9° angle and still allow the computer to be mounted forward. The two super durable o-rings secure it to the bar, and the patent-pending X-Lock design will prevent the computer from being knocked out. The X-Lock securely fastens the GPS computer to the mount by pressing down at a 45° angle and rotating it forward until it "locks" into place.Worry-Free Riding Over Any Type of TerrainTwo Sets of O-Rings (Two Diameters) Plus A Backup O-Ring in Each SizeRubber ShimX-lock Composite Mounting Bracket