Size and Fit: The self-locking bit holder has a length of 60 mm, a width of 23 mm, and a 6.3 mm hex socket and hex shank, making it ideal for use with drills, screwdrivers, and wrenches for quick and easy installation. Quick Change: The 6.35 mm hex extension shank has a pop-up connector that can be quickly attached by simply pressing the connector, saving time and effort. It is coupled with a high-quality built-in spring so that the connector is self-locking and holds the bit firmly in place as soon as installation is complete. The bit pops out instantly when the connector is pressed down to release it, making it very convenient and easy to use. Quality Materials: Made of high-quality iron, the self-locking bit holder has high hardness, is not easy to deform, is corrosion-resistant, and rust-resistant, making it suitable for long-term use. Simple Installation: The quick-release chuck adapter is very easy to use and only requires a few steps to complete: 1. Pull the self-locking head down. 2. Insert the bit. 3. Loosen it, and the self-locking sleeve will automatically return to its original position. Widely Used: Ideal for maintenance workers, the 1/4" hex extension rod can be quickly mounted on most electric drills, screwdrivers, air wrenches, and more to secure hex shank bits, Phillips bits, sockets, and more, making it convenient for you to use drills, saving you a lot of time, and improving your work efficiency.