JPT SCREW SHPT1 is suitable for nylon, PVC, PC, aldehyde resin, glass, transparent acrylic, polycabonate resin etc. JPT2 is suitable for Bakelite, PC+glass fiber, magnetic powder, porcelain powder, aluminum and magnesium powder, iron powder, electric plastic machinery etc. HPT3 possesses two unique features that JPT1 and JPT2 have possesses, I. E. (wear-proof, corrosion-proof, heat-proof, high-pressure proof and high-speed proof) The above three materials (bimetallic screw is called fully hardy screw abroad)replaced common bimetallic material and being widely used abroad.