Gantry cranes are easily mobile on (4) 8" swivel casters with four-position lockers. Cranes with capacities from 2,000 to 4,000 have glass filled nylon casters and 6,000 to 8,000 capacity models have phenolic casters. Our 10k capacity gantry crane has steel casters. Height is adjustable in 6 inch increments. Customers should be sure to not move units while loaded, this is very dangerous!