Precision extruded aluminum alloy inner and outer tubes, combined with twin alignment bushings, ensures a precision alignment. The anodized finish keeps the tubes virtually corrosion free. Revolutionary adjustable mount & swivel system. Engineered to be the strongest swivel mechanism in the industry, it is also the first mounting system that can be adjusted to any desired height. Integrated pull pin with ergonomic grip makes it easy to swivel into position for lifting or transport. Smooth wheel performance. Twin track 7" diameter wheels are designed to roll independently to make changing direction smooth and effortless. 5-1/2" wide wheel base adds superior stability. 1600 lb. lift capacity. Extends 9-1/2". Fits frame sizes : 3" x 3", 4" x 3". Fulton #1413130034 fits 5" x 3" Frames.