Description: 【Material】: Woodworking Drill Tools is made of steel, high hardness, strong and durable. Heat treatment, high hardness, lengthened core, high concentricity, long life using. 【Convenient Chip Removal】: Auger Mortising Chisels Drill has a standard chip removal design, which can easily remove the side of wood chips and improve drilling efficiency 【Advantage】: Wood Drill Bit Set reduce the labor intensity of construction workers, accelerate the construction speed, reduce the construction cost of construction, installation, decoration, decoration industry. 【Wide Application】: Square hole drill bit fits all mortising machines and drill press attachments. Square hole drill is mainly used for woodworking aspects. 【Easy to Use】The Mortising Chisels consists of two parts, round Core drilling and square drilling ( as picture show ).when installing ,this two parts need to be held tightly by a clamp. Specification: 7Pcs A Specification: (6.4/8/9.5/12.7/14/16/19mm) 7Pcs B Specification: (6/6.4/8/9.5/10/12.7/14mm) 5Pcs Specification: (6.4/8/9.5/11/12.7mm) 3Pcs Specification: (8/9.5/12.7mm) Package Includes: Optional Package 7Pcs or 5Pcs Or 3Pcs Square Hole Drill Bit Note: Please allow slightly errors due to manual measurement and different monitors.