This hand truck features cradles to safely carry two different sizes of oxygen, acetylene or nitrogen cylinders are 9-1/4" Dia Type K, and 12-1/4" Dia Type LP or 12" Dia Type XF. Folding rear support uses a spring-loaded lock mechanism to easily convert from two-wheel to four-wheel mode for added stability. Cylinder truck is constructed of welded tubular steel for strength and includes safety chains to help secure the cylinders. Rolls smoothly on 10" mold-on rubber wheels; four-wheel position offers 4" rubber swivel casters for easy maneuvering. Easy assembly.