"Cotterman 5-step rolling ladder with two 10in. semi-pneumatic rear wheels provides easy entry to tractor trailers in places where loading docks and bays are not available. U.S.A. Item is on backorder until early May. Base Size W x D in. 32 x 60, Caster Type Semipneumatic rear wheels, Steps qty. 5, Step Type Grip strut, Step Width in. 24, OSHA Approved Yes, Caster Size in. 10, Finish Type Gray powder coat. Slip resistant heavy-duty grip strut treads Gray powder coat finish resists corrosion California residents need to order item # 1439931"