The raw material is made of Al-Cr-Mo alloy steel (SACM645). The screw will have gas nitriding heat treatment for 150 hours. Grinding process will be applied to the screw surface for two times to ensure the size is in precision. The final screw product will be chrome-plated on the surface to level up the quality. Both of the in house design barrels and the customized design barrels can be provided.