Excavator Undercarriage Parts ZX330 Track Roller For Excavator Bottom Roller 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. Our products are according to the standard of OEM to manufacture.