"One-piece construction, dual heat treated for maximum strength","Locking mechanism specifically designed for impact use, and knurled sleeve designed to encapsulate the retaining ring to protect work environment and the tool","Positive pin lock design prevents accidental socket removal","Female end of the tool has a lead in angle of 45°, allowing for easy installation of impact gun. Recess machined into female end is designed specifically for new style impact gun","Includes sizes: 3\", 6\", 12\" 3 PIECE 3/8" DRIVE LOCKING IMPACT EXTENSION SET SBXP3L | Matco Tools