Includes 3-pc. 3/4 in. drive extensions: 4, 8, 16 in. Knurled band provides grip for starting or turning loosened fasteners with fingertips Detent grooves offer a secure connection with the drive tool and a drilled through-hole allows locking with retaining pin Spring-loaded retaining ball latches into sockets and holdsthem securely in place Polished, chrome-plated finish is easy to clean and highly resistant to corrosion Beveled drive end helps guide extension smoothly onto drive tool Radiused corners inside the drive avoid stress concentrations that can cause cracking