Motion provided by power generator of an excavator is conveyed to track link by running motor and sprocket rim. The teeth of sprocket rim should fit the track link well and should be able to drive the link steadily. Even when the link stretches due to wear and uz teat of its pin and bushing, the teeth should fit well usually, a sprocket rim is placed at the back part of the running device of an excavator. Our products are according to the standard of OEM to manufacture.