Liner Barrels (Sleeve Type) are developed for high wear resistance outer body made out of Alloy steel and inner liners are made of Tool alloy steel for high wear resistance for high abrasive polymers like Nylon with glass filled, Pc, Antifabs, Toner etc. Liners are treated with Vacuum hardened, Plasma Nitriding, and Cryogenic for better core hardness, Ultra surface hardness & close molecules. Water circulation jacket to control friction heat is standard features.