1. The shell is made of high-class alloy steel,and it adopt advanced plastic plating technology both inside and outside,beautiful and rust protection. 2. The space is tested by accurate measurement and the design can efficiently avoid the jam, chain clasp. 3.The gears are made of international standard gear steel with a smooth surfaceand high wear- resisting degree. Compared with common gears,they are more steadier and laborsaving. 0.5t-20t 1m-30m
