Whiteside creeper with wide seat bottom is less fatiguing, rise on the seat back helps to support the lower back. 3 casters swivel easily. No rust, framework powder coated. Magnetic strip in tray for small parts. Seat height 16-1/4, width 18-1/4, backrest height 23-3/4, length 16. Seat box: height 24, width 18-1/2, length 16-3/4. Extra Casters sold separately (WHI-33 box of 4). Please call for details.