Choc for up to 32" tire diameter: NFPA standards require Wheel Chocs to be mounted on fire apparatus before bening placed in service per NFPA 1901-09. Further, our AC-32 choc complies with SAEJ348 standard for Wheel Chocs. This standard presents basic criteria for the design, manufacture and testing of wheel chocs. Zico Chocs feature high-ternsile strength aluminum construction, large rear opening hand grip, and double row of rugged teeth to grip almost any firm surface. WARNING: undersized chocs may fail to restrain vehicle . The vehicle may either roll over or crush an undersized choc, possibly resulting in bodily injury or property damage. The AC-32 is: 8-1/2" high, 8" Wide and 14-13/16" long. It weighs 7.5 pounds.It meets SAEJ348 for up to 32" tire diameter. Please see our QCH-32-H for a horizontal choc holder or the QCH-32-V for a vertical choc holder. Model QCH-SL Safety latch may be added to any ZICO horizontal choc holder.