The Techni-Pro 758IE712 is a shelving system with plastic split sleeves (4/bags). Meet any storage requirement—and save money—with our multi-use, easy-to-configure shelving system. Posts are numbered in 1" increments to make adjusting shelves easy and come with leveling bolts. For a mobile system, add stem casters with 5" non-marking, easy-roll, shock-absorbing poly wheels. For cart applications, donut bumpers provide additional shock absorption, and there is a 30" U-handle assembly for 18", 21", and 24" shelves.