The sprocket is composed of collar、idler shell、shaft、seal、o-ring、bushing bronze、lock pin plug，the idler is applicable to special model of crawler type excavators and bulldozers from 0.8T to 100T.it is widely applied in bulldozers and excavators of Caterpillar,Komatsu,Hitachi,Kobelco,Kubota,Yanmar and Hyundai etc,have different manufacturing technology,like casting,welding and forging,use precision processing technology and special heat treatment technique to reach best wear-resistance and have maximum extent loading capacity as well as anti-cracking. The function of an idler is to guide the track links into running smoothly and to prevent dislocation,idlers also carry some weight and therefore increasing groud pressure.there is also an arm in the center which supports the track link and guides the two sides.the smaller the distance between the idler and track roller,the better the orientation. Our products are according to the standard of OEM to manufacture.