A. Professional design: It is quite suitable to use a mortising machine or mortising accessories to drill square holes in wood. B. Applicability: It is suitable for most mortising machines and drill bit accessories. C. Main use: Square hole drill bits are commonly used in the woodworking industry. D. Materials and dimensions: It is made of high - speed steel. After heat treatment, it has relatively high hardness, a long cutter core, and high concentricity. There are 4 different sizes, namely 1/4 inch (6.35 mm), 5/16 inch (7.94 mm), 3/8 inch (9.5 mm), and 1/2 inch (12.7 mm). E. Reasons for choosing this product: In industries such as construction, installation, and decoration, it can help reduce the labor intensity of construction workers, speed up the construction progress, and cut down construction costs. F. Packaging contents: 1 drill bit of 1/4 inch (6.35 mm); 1 drill bit of 5/16 inch (7.94 mm); 1 drill bit of 3/8 inch (9.5 mm); 1 drill bit of 1/2 inch (12.7 mm). G. Precautions: Tools such as electric drills and hammers are needed to drill square holes.