The Industrial Steel Gantry Crane AHS-6-20-16 is designed for transporting and positioning materials along the beams length. The solid steel construction will provide years of service. Unit comes standard four (4) position locking swivel casters with roller bearings. Locks the rigging in 1 of 4 positions; you can set the wheels and push the gantry crane forward, back, left or right. There is an optional Total Locking Casters that lock the rigging in any position and locks the wheel from rotating. More economical and flexible than permanent cranes and features a quick setup design. Painted blue finish with warning and operating stickers and complete owner's manual. Designed for semi-permanent or permanent applications. Requires assistance from fork truck to set-up.