Usage: suitable for screwdriver handle or electric screwdriver tool ( three-jaw chucks) 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 3 / 8 " Extension Drill Bit Set Power Tool Unique Design: the antidropping steel ball is better fixed: the automatic locking device is not easy to slip or fall off and cause dangerously situations Greater bearing capacity Using high-carbon steel, wear-resistant, wear-resistant, and long service life of Application: It can be used for installation on tool with shapes such as screwdriver, electric screwdriver, air drills, electric drills, and manual screwdriver, Manufacturer: ERRORY