Convertible Head: 1 / 4 handle can be converted to 6.35mm square for head, 3 / 8 handle can be converted to 9.5mm square for head, 1 / 2 handle can be converted to 12.7mm square for head of Application: It can be used for installation on tools with shapes such as pneumatic screwdrivers, electric screwdrivers, air drills, electric drills, and manual screwdrivers Unique Design: the anti-dropping steel ball is better fixed: the self-locking device is not easy to slip or fall off and cause situations double R design, greater bearing capacity Usage: suitable for screwdriver handle or electric screwdriver tool (three-jaw chuck) to drive the sleeve After installation, the joint can be converted into a square for head, which can be used for the installation of the sleeve A powerful tool for conversion Various Specifications: 1 / 4 " 3 / 8 " 1 / 2 " Extension Drill Bits Bit Set Power Tools, Manufacturer: Thatiarry