Kent-Moore KMO-187-10 Cylinder Head Wrench Attachment For use with tension wrench or standard 1/2" drive socket set handles. This tool has double hexagon openings (3/4") and square openings for all standard 1/2" square drive socket handles. The KMO-187-10 wide sweep cylinder head wrench attachment is for “hard to reach” center bolts. See your shop manual for recommended bolt tensions and proper order of tightening. Weight 1 lb.