"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. Caster Type Semipneumatic rear wheels, Base Size W x D in. 32 x 60, Steps qty. 5, Step Width in. 24, Step Type Grip strut, Caster Size in. 10, Finish Type Gray powder coat, OSHA Approved Yes. Slip resistant heavy-duty grip strut treads Gray powder coat finish resists corrosion California residents need to order item # 1439931"