Made from HSS The gears are made from HSS and the stiffness varies from the hole saw has a twist drill bit inside, which is non-removable. ANDLong life Low consumption anti-cutting for long life. ETQuick cutting Suitable for electric hand drill, motorized drill and mobile tape type magnetic drilling machine. ETMulti -Usage: Perfect for installing knobs, locks and cutting holes in wood, mild steel, etc. High speed steel material, durable and practical. The Triangular shank prevents drill bits from slipping and provides stable operation. Sharp teeth, computer indexing, high-speed grinding, high precision, less hole opening error. 2mm drilling wall thickness, increases the life of the drill. Perfect for installing locks, knobs in doors and cabinets or drilling larger diameter holes to across desks, etc. Cuts steel, stainless steel, copper, brass, aluminum, fiberglass, formica and other laminates in seconds.< /p> Application for thin metal, iron plate, pipeline steel, aluminum alloy. Material: high speed steel. Outer diameter: 22 mm. Length: 65 mm (approximately). Optimal rotation speed: 280 ~ 300 rpm. Package weight: 64 g. Package dimensions (L x W x H): 105 x 30 x 30 mm. Delivery quantity: 2 piece luckymeet