9 pieces of Impact Spline 12 point Socket Bit Set Kits: M-4, 5, 6, 8, 9, 10, 12, 14, 16 The socket bits are 3-1/8" (80mm) long. 1/2" (12.7mm) Sqaure Drive with drive release holes. Drop forged black chrome moly steel (CR-MO). | Industrial grade quality. Suitable for air tools and electric tools. US-BASED CUSTOMER SERVICE: Available by chat, email, phone, or visit us at our customer service center in La Crosse, WI.