Heavy Duty Plain Trolleys is designed for low maintenance and trouble-free operation. It is used to mobilize the hoists. It is used with wide-flange H-beam and standard I-beams, or curved track. It has hardened wheels lubricated for life, double sealed ball bearings. It has the capacities of 1½ to 20 ton. The features are load-bearing parts are only stressed to 20% of their limit, Pivot mounted for smooth operation and load balancing, heat-treated steel wheels are hardened for long, trouble-free life, lifetime lubricated ball bearings increase reliability and reduce maintenance, adjustable to fit any beam-tapered or flat flanged, easily adapted for your shop or plant, low minimum radius for curved beams for smooth travel around tight curves.