Material: high speed steel, high hardness. Sturdy and durable 6 sizes: 16mm (0.62 inch), 18.5mm (0.72 inch), 20mm (0.78 inch), 25mm (0.98 inch) , 30mm (1.18 inch)，32mm (1.25 inch). Meet Your Different Needs Practical Design: The hole cutter uses spring-loaded design, which is favorable for chip removal, drilling efficiency is higher Widely Used: Widely used for cutting holes in a variety of materials such as wood, plastic, PVC sheet, insulation board, thin iron, copper, aluminum alloy, steel, etc. Hole saw drill bit set is specially designed for finer steel bits, ideal for installing locks, knobs in doors and cabinets or for drilling larger holes diameter Product Description: New and high quality. Material: High speed steel, high hardness, sharp blade, high precision Size: 16mm (0.62 inch), 18.5mm (0.72 inch), 20 mm (0.78 inch), 25mm (0.98 inch), 30mm (1.18 inch)，32mm (1.25 inch) The TANGGER 6PCS hole saw drill bit suitable for stainless steel, iron, aluminum, fiberglass and various types of pipes. It is ideal for home improvement and house construction. Delivery: 1x16MM Hole Saw Drill Bit 1x 18.5MM circular saw drill bit 1x 20MM hole saw 1x 25MM hole saw 1x 30MM hole saw 1x 32MM Hole Saw Note: 1 Make sure the drill bits and plate are at 90° angle when using hole saw kit. 2 Cut the metal slowly without hitting it, and the larger the saw, the lower the number of revolutions. 3 Do not overtighten the grub screws, otherwise they will fall out. 4 Coolant is recommended. And clean up any debris before drilling.