Milwaukee 1/2" Drive 21-mm Standard Socket w/FOUR FLAT™ Sides is designed for versatility, making it an essential addition to any toolbox. This socket features four parallel flat sides that help prevent rolling and provide wrench-ready capabilities, enhancing ease of use and safety on the job. Clearly stamped with its size, it allows for quick and easy identification, saving you time during your work. The deep socket is engineered with optimized geometry to reduce bolt rounding and stripping, ensuring a secure fit and longer tool life. This combination of thoughtful design and durable construction makes it for both professional and DIY applications. Model Number: 45-34-9122