Features:1. This saw drill bit is made of special steel, heat treatment, HRC48-50, offers high hardness, lengthened core, and high concentricity.2. Professional drill bit, suitable for construction, installation, renovation, decoration industry, etc.3. It will get double effect by matched use with mortise and tenon machine, the square hole punching needs to use electric drill, hammer & other tools.4. 6 pieces a pack with different slot diameter to meet your needs.5. Great accessory for mortising, chisel, and woodworking. Specifications: Condition: 100% Brand New and High Quality Material: Steel Hardness: HRC 48-50 Color: Silver Quantity: 6Pcs Support Diameter: Approx. 19mm / 0.7inch Corebit Length: Approx. 200mm / 7.8inch Model Slot Diameter Weight 001 1/4inch (6.4mm) 106g 002 5/16inch (8mm) 131g 003 3/8inch (9.5mm) 154g 004 1/2inch (12.7mm) 195g 005 9/16inch (14mm) 214g 006 5/8inch (16mm) 222g Weight: Approx. 1215g Package Included: 6 x Saw Drills