ATD Blow Molded Mechanic's Creeper features un-restricted arm movement. 2 molded-in tool trays. 6, 3" swivel wheels (ATD-81004). 1" ground clearance. 39.75"L x 4.25"H x 19"W. The wheels are fitted with multi-terrain treaded rubber wheels. These wheels are industrial strength, oil, chemical and grease resistant with encapsulated ball bearings. 90 Day Warranty.