Dual helix cutter head provides smoother and faster auger action, even through nail embedded timbers. Full body hardened machine steel assures durability, minimizes warping and delivers long lasting performance. Fully hardened through the entire bit. Oversized lead section provides pulling power through thick timbers. Quick gripping power with superior penetration. Speeds the installation of wires in any wood construction.7 1/2 in. length, 7/8 in. diameter