For fast, small hole drilling in wood. Made of heat-treated high-carbon steel, the flat boring bit bores clean holes atany angle in wood, plastic, plywood, and formica. The drill point and cutting edges can be resharpened often for economical hole drilling. Bit offers a 6" drilling depth, but can be used with 12" extension for extended deep hole drilling. 1/4" shank. Set includes 1 each: 3/8", 1/2", 5/8", 3/4", 7/8", and 1".