A 9 piece set, for use on hard to reach auxiliary (serpentine) belts. Socket sizes: 13, 15, 16, 18mm. Crows Foot sizes: 13, 14, 15mm in 3/8""D & 1/2""D. Socket sizes: 13, 15, 16, 18mm. Crow's Foot sizes: 13, 14, 15mm. 3/8""D and 1/2""D. For use on hard to reach auxiliary belts. For use on hard to reach auxiliary belts.