Series 900 Harper Trucks are identical to Series 940 except they are equipped with a center tow ring for slow speed towing for on job site transportation. Comes with a lock top tool box. Series 950 Extra Heavy Duty Cylinder Truck is the only model designed to be lifted and placed in a construction type application. Containment rings and center "V" on the base plate, coupled with the "Sur-Lok" Cylinder holding device securely carries cylinders on the ground or during hoisting into place. Handle large cylinders.