Very well made with full coupler and brass stop ring this is a rebuildable unit and commercial heavy duty quality. Piston Collar Thread Length in. Aluminum bronze bearing reduces wear caused by off-center loads, maximum spring force speeds piston retraction, solid steel body for durability, chrome plated piston rod resists wear & corrosion, base mounting holes for positioning. Maximum sized springs speed piston return and increase spring life. Solid steel cylinder body for durability. Chrome plated piston rod resists wear and corrosion. Wide range of accessories available to thread...