Stepped Design with Two Sizes to Work on Ford and Cadillac Vehicles. Similar in function to our 39960 plastic model but made from metal and in a scissor design. Use 3/8 size for 2003 - 2010 Ford V8 Explorer, 2004 and later Ford F150 and Cadillac CS. Use 1/2 size for Ford Super Duty Trucks, F250, F350 and F450.