1/4" square drive extension bar with ball lock. Flexible lock system either for permanent interlocking or fast change of accessories, free-turning sleeve for rapid tightening or loosening of screws & nuts, chrome vanadium, brushed chrome-plated finish. By using this flexible-lock system, attachments can be fixed to the extension permanently, preventing slipping & any unintentional loss of the attachment. When the lock is deactivated the sockets can be attached as usual & changed in a flash. The free turning sleeve on the extension effectively speeds up the tightening or loosening of screws & bolts.