Yakima Viper Bike Mount Simple tool-free installation and removal of the bike mount from your car roof rack Skewer design allows one-handed adjustment Streamlined tray compatible with most disc brakes and doesnt touch the painted surfaces of your bike The most bang for your buck in the top of car category with Lockable skewer that keeps your bike safe and sound (Yakima SKS Lock Cores sold separately).Fits round or square crossbars only Love it 'Till You Leave It Limited Lifetime Warranty.