Bobcat 325 18 Hole 21 Teeth 6813372, the older sprocket was 9 Holes 21 Teeth 6811940 Aftermarket Undercarriage Components Part Number.
This sprocket also fits Bobcat 331, 328 and 334 mini excavators. Please count the bolt holes in your Bobcat sprocket to assure your getting the correct one, as these sprockets are also available in 12 bolts holes with 21 teeth.