5 Piece SAE/Metric Wheel Socket Set. No more scratches on your prized, expensive car wheels! These combination steel/aluminum sockets are a must for wheel/tire repair specialist. Combining the strength of steel with the resilience of aluminum. These combination sockets offer the best solution for safe, non-damaging power wrench applications. These unique, purpose design sockets may be used safely with impact wrenches on alloy wheels and polished or coated wheel bolts/nuts without damaging the coated or polished surface of the bolts/nuts on the wheel. SAE sizes: 3/16" and 7/8" Metric sizes: 17mm, 19mm and 21mm.