Our factory produce the Sleeve barrel ,and Bushing for hoisting machine travelling hoist winding machine digger lift shaft elevating conveyer winding engine hoisting gear , hoister ; elevater ; 1.The Sleeve barrel come with high-quality alloy structural steel 42CrMo, 2.Hardness: HRC55-58, through overall quenching 3. Bushing Operational life span: 30,000 hours or more