Professional contractors rely on DEWALT Self-Feed Wood-Drilling Bits when they need to bore holes 1" or larger for pipes, cables, and ductwork. Select sizes of these ultra-heavy-duty bits feature a triple-cutter design** that delivers long life, minimal binding and fast chip ejection. An aggressive self-feeding screw-tip pull the bit easily through the toughest materials. Standard 7/16" Quick Change Shank allows for fast bit changes in quick change ready tools like the FLEXVOLT 60V MAX* Brushless Cordless Quick-Change Stud and Joist Drill (DCD471) while preserving backward compatibility with chuck based non quick connect tools. * Maximum initial battery voltage (measured without a workload) is 60 volts. Nominal voltage is 54 Set includes 1-3/8", 1-1/2", 2-1/8" & 2-9/16" diameter bits with 5-1/2" extension. The self-feed bits in DeWalt's DW1648 five-piece kit make use of aggressive, replaceable spurs and a unique two-cutter design to cut rough holes in wood quickly and efficiently. The geometry of these bits is engineered to provide extended bit life, and an open-tooth design allows extra sharpenings to save you money. Also offering a 7/16-inch ball groove shank that has flat sides to prevent the bit from slipping in your drill's chuck and allows you to switch from one application to the next quickly, this kit includes a 5-1/2-inch extension piece, 1-3/8-, 1-1/2-, 1-1/8-, and 2-9/16-inch self-feed bits, and a convenient set of replacement parts in a durable kit box that makes it easy for you to keep your tool kit organized on the go.