Milwaukee 48-20-5324 - 3-1/8" X 22" One Piece SDS-MAX Tunnel BitThe MILWAUKEE 3 1 8" X 22" SDS Max Tunnel Bits are ideal for drilling deep, large holes in concrete, concrete with rebar, brick, and block. The high volume sloped flutes and 22" long shaft allow for continuous deep hole drilling and faster dust removal avoiding the need to clear out a core. These concrete drill bits feature a robust head equipped with a 3 cutter design and sharp carbide centering tip for precise starts and fast grinding of concrete