These power bits are specifically designed to fit in between building studs for the installation of conduits and wires. Ideal use is with power angle drills. These single spur- double twist wood drills are heat treated with machine ground hollows. The self feeding screw ensures easy starts and positive position without drill walking. The overall length of the drills is 8-1/2". Shanks have two set screw recesses for use with power bit extensions. Series 304BU is designed specifically for electrician's applications.