Thule, Snug Tite Lock;

Slapping all your bikes onto your rack is necessary but occasionally nerve wracking, but Thule's Snug Tite Lock takes some of the worry out of your trip with a bomber construction that helps secure your Hitch Post Pro rack to your hitch. It also makes it significantly harder for someone to lift the rack off your hitch when you stop for a burger, fits both 2in and 1. 25in hitch carriers, and has a swappable lock cylinder that lets you use it with different Thule models (other cylinders are sold separately).