This sprocket is used for mini excavator of CATERPILLAR , material is 50Mn or 45SIMN,the hardness is about HRC55-58,KTS factory professional produce high quality excavator parts for many years,special 1-6ton mini-excavator undercarriage parts,not only can be used in steel tracks,also can be used in rubber tracks. Our products are according to the standard of OEM to manufacture.