The Milwaukee Tool 48-28-1050 18" X 7/16" Universal Quik-Lok Extension is a high-quality carbon steel extension designed for use with hole saws and cutters. It features a length of 22.7 inches and a 7/16 inch shank size, making it compatible with a variety of tools. This bit extension is ideal for deep-hole cutting applications and comes with a manufacturer warranty of 1 year. With a weight of 1.4 pounds, it is lightweight and easy to handle during use.