The screws ans another consisting parts are designed respectively against the featues of different materials such as PP, PE, PS, ABS, PA, PVC, PC, POM, EVA, LCP, PET, PMMA etc. They are suitable for the purpose of features the screw and barrel with good tear and wear resistance, good compounding effect and hith ppoduction. Airexhausted system or common vented hole can get rid of water and waste gas out of the xxxxx enables more stable extrusion and more solid pellet, co the super quality of product is guaranteed.