Global Industrial I Beam Trolley 10,000 Pound Capacity Adjusts to fit width of beam. Self-aligning frame and ball bearing wheels. Usable on straight or curved track. 1 Year Limited Warranty. Features: Extra strong hardened wheels and axles allow the Trolley to roll smothly on beamsSuspenstion plate has an opening that allows for easy hook attachements. Spacer washers are included to adjust the trolley to fit the beam widthSteel equilizer pin is enclosed for long lasting strengh and durability.