Housing material is high density aluminium alloy ADC-12. Gear profile type ZK which efficiency up to 0.9. Other China made gear profile type is in ZA which efficiency up to 0.7 only. Hobbing tools for ZK profile are much expensive more than 10 times than ZA. Material of worm shaft is 40Cr (ASTM 5140). Others makers are using 45# steel which quality is poor while using it as worm shaft. Material of brass on worm wheel is ZQSnD10-1 (DIN GB-CuSn10/2.1051)(BS PB1) which other China makers are using ZQSND9-4 only. Bearings from FAG bearings China OEM makers. Synthetic lubrication oil of TAXAS brand. 100% running test before ex-factory.