Features: brand new and high quality 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. Scope 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 dangerous situations. double R groove 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 Bar Bit Set Power Tools. Specifications: Material: Vanadium Steel Product Dimension: approx. 50mm/ 1.97 inches approx. 65-73mm/ 2.56-2.87 inches Net Weight: 70g/ 0.15 lbs 90g/ 0.20 lbs Note: Please allow 1-2cm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1 SET Socket Adapter