SURE GRIP ALUMINUM WHEEL & TIRE CHOCK CHOCK TRAILERS OFF-HIGHWAY CONSTRUCTION EQUIPMENT BUSES AIRCRAFT AND OTHER HEAVILY LOADED VEHICLES...HELP PROTECT AGAINST RUNAWAY VEHICLE ACCIDENTS. BUILT-IN TRACTION GRIPPERS CREATE MAXIMUM FRICTION BETWEEN THE TIRE AND THE PARKING SURFACE. MEETS OSHA REQUIREMENT 1910.178(K)(1) THAT STATES ""THE BRAKES OF HIGHWAY TRUCKS SHALL BE SET AND WHEEL CHOCKS PLACED UNDER THE REAR WHEELS TO PREVENT THE TRUCKS FROM ROLLING WHILE THEY ARE BOARDED WITH POWERED INDUSTRIAL TRUCKS"". WARNING: This product can expose you to chemicals including lead which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65warnings.ca.gov -