DESIGNED Professional Great for drilling square holes in wood with a mortising machine or a mortising attachment.Fits all mortising machines and drill press attachments. Square hole drill is mainly used for woodworking aspects. MATERIAL & SIZE Made of high-speed steel. Heat treatment, HRC48~50, high hardness, lengthened core, high concentricity; 4 Different size include 1/4" (6.35mm), 5/16" (7.94mm), 3/8" (9.5mm), 1/2" (12.7mm) WHY CHOOSE THIS ITEMReduce labor intensity of construction workers, speed up the construction speed, reduce construction costs for construction, installation, renovation, decoration industries. PACKAGE CONTENT 1Pcs 1/4" (6.35mm); 1Pcs 5/16" (7.94mm); 1Pcs 3/8" (9.5mm); 1Pcs 1/2" (12.7mm) NOTEThe square hole punching needs to use electric drill, hammer & other tools.(All of these are not include) Features: 1.Professional wood drill bit, suitable for construction, installation, renovation, decoration industry, etc. 2.The 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. 3.The dimension refers to the length of the square hole drilled by the square hole. 4.The cylinder diameter of the clamped portion is 19mm/0.74inch. 5.The square hole drilling core we sell are more than 210mm, belong to longer drilling core. Specification: Size:1/4inch(6.35mm), 5/16inch(7.94mm), 3/8inch(9.5mm), 1/2inch(12.7mm) Material: High-speed steel DIY Supplies: Woodworking Use: Wood Drilling / Punching Package Content: 1 Pcs 1/4 Inch Twist Drill 1 Pcs 5/16 Inch Twist Drill 1 Pcs 3/8 Inch Twist Drill 1 Pcs 1/2 Inch Twist Drill Note: 1,Please allow 1-3cm differs due to manual measurement. 2,Due to the different display and different light, the picture may not reflect the actual color of the item. Thanks for your understanding. Sell from QISF(Quality Innovation Service FIRST) Store