Thule Bed Rider XTR Lockable skewer with single-side adjustment makes it easy to secure the bike to the carrier for stable and secure bicycle transport Aluminum telescoping bar with soft grip rubber feet hold carrier on side rails of pick-up trucks without drilling (Not over-the-rail bed liners) 3 Thule One-key lock cylinders included to lock the bikes to the carrier and the carrier to the truck Additional bikes can be transported with the Thule locking bed-rider add-on block (#Brlb2, sold separately) Will Not work on trucks with over the rail bed liners