Jet PT Series Plain Trolleys Welded heavy gauge steel frame and powder coat finish provide maximum durability and protection. Hardened large steel wheels and thicker double sealed lubricated ball bearings provide smooth movement. Built-in bumper guards on the side plates increase safety and extend trolley life. Easily adjustable to wide-flange H-beams, standard I-beams or curved track with the included spacer washers. Pack of 1