The Milwaukee® 7-1/2 in extension for large thin wall core bits expands your drilling capacity. Made of high-quality steel, the extension extends your drilling by upto 7-1/2 in it attaches easily to SDS PLUS® core bit adapters and features smooth, tough thin core construction for dependability. For deeper drilling, use the extension with a Milwaukee® 8 in or 12 in SDS PLUS® adapter shank. Milwaukee® Drill Extension, 1-3/4 in Drill, 7-1/2 in Length, Steel, For Use With: 1-3/4 to 6 in Dia Thinwall Core Bit