Lynx Stop ‘N Chocks include 2 chocks per box. Leveling your RV has never been easier because Tri-Lynx offers the only self-positioning guide. Now you’ll hit the top of the stack each time. They are the ideal assistant for your original Lynx Levelers. Just place the Stop -N Chock on a stack of Lynx Levelers, butt the stack up to the wheels, slowly idle your RV to the top of the stack until you Stop -N Chock. It’s that easy! They are tough and durable and simple to clean. 8.5 inch x 8.5 inch x 6 inch.