FEATURES: Various existing bits, can only process a circular hole, square hole can not be processed, to machining square hole, must drill the hole or cutting machine processed crude hole, then chisel made from artificial hand. This utility model in the hole drilled by the rotary body, while the impact of the use of hammer impact force transmitted to the outer body, the material crushing round hole and square head wall, a one-time processing of a square hole, and the dust can be broken slag discharged from the tube. Using different specifications of the square hole drill, matching the appropriate power of the square hole machine, you can play a square hole to meet the requirements. Professional wood drill, suitable for construction, installation, decoration, decoration and other industries. Specifications: Material: HSS ;Hardness: HRC 4850 Holder diameter: 19mm (circular) ;Drilling core length: 200mm Slotting flute diameter:1/4 Inch (6.4mm), 5/16 Inch (8mm), 3/8 Inch (9.5mm), 1/2 Inch (12.7mm), 9/16 Inch (14mm), 5/8 Inch(16mm). Package Included: 1 x 5/8-inch (16mm) 1 x 9/16-inch (14mm) 1 x 1/2-Inch(12.7mm) 1 x 3/8-Inch(9.5mm) 1 x 5/16-Inch(8mm) 1 x 1/4-Inch(6.4mm)