Milwaukee?s 1-Piece carbide tipped tunnel bits are ideal for drilling large holes where the depth of the hole exceeds the practicality of a core bit. These tunnel bits come in diameters ranging from 1-1/2 in. to 3-1/8 in. with overall lengths of 12-1/4 in., 22 in. or 39 in. The chisel and racer teeth are optimized for faster material pulverization. The SDS-Max shank 1-piece design maximizes energy transfer while the wide land and substantial core thickness makes these tunnel bits durable even in large hammers. The centering tip reduces bit walking for exact spot drilling. The three wide flutes create true round holes while ejecting debris fast.