Clamping Kit, T-Slot, Number of Pieces 52, Slot Size 9/16 in, For Use With Drilling Machines, Lathes, Milling Machines, Includes (6) Step Blocks, Material - Machining Steel, Application For Fixing Each Kind of Working Piece on Machining Table, Features All the Blocks, Bolts, Nuts and Hold-Downs are Case Hardened. Racks Can Be Bolted to the Wall or Side of Machine for Easy Access, Finish - Machining Black Oxide