CONVENINET DESIGN: It has been well organized in a convenient plastic storage case. Helping you easy carrying out for working.Includes Hex Key and Installation Plate. Hole saw with 11 pieces in a kit. SAFETY AND DURABLE: Carbon Steel, Heat Treated. The special gear design makes the hole more accurate. High speed steel teeth for fast and clean cuts.Suitable for normal wood,don't try it to hard material.It will happen broken. PERFECT FOE HOLE: Covers most popular hole saw sizes on the market. It's perfect to make any holes you need.High precision, smooth cutting edges, especially impact resistance, wear resistance, cutting depth 25 mm. CARBON STEEL MATERIAL - High speed steel teeth for fast and clean cuts, special gear design makes the hole more accurate. Read Less