Drill Bit Extensions features: Hole Opener Drill Bit For Wood Aluminum Iron Sheet Pipe Plastic 80mm(90mm) Color: we send based on the color or size of the main image of the product page. Quantity：we send based on quantity on title, if there is no quantity in the title, we send based on description. Size:90mm 10 SELECTABLE HOLE DIAMETERS80mm, 85mm,90mm,95mm,100mm,105mm,110mm,115mm,120mm,solutions to all dimensions of the problem. HEAT TREATED M42 HSS Bi-metal HOLE SAWMade of HSS carbon steel & Bi-metal steel with sharp edges and high hardness. strong and sturdy. The precision of the concentric degree, so that the teeth edge of the uniform, to extend the life of the hole. CUTTING DESIGNWith the non-binding clean edge design, this hole saw cuts smooth and easy. And the spring on the drill bit would automatically pushes the disc out of the saw immediately after completing the hole. APPLICATION Suitable for cut Mild Steel, Stainless Steel, Cast Iron, Brass, Aluminium, Wood etc.,Perfect for Installing Locks, Knobs in Doors and Cabinets or Drilling Larger Diameter Holes Through Desks etc., Carpentry decoration essential tool. Usage Suggestion Hole saw may become overheated and get damaged or even burned up due to fast rotary friction, we suggest customers to use cutting fluid to keep the hole saw cold during usage. Keep the drill be stable when drilling, otherwise the centre bit may get snapped due to excessive shaking. Start drilling with a slow drill rotary speed, or the centre bit may be shattered on first use. The larger the hole saw is, the slower the drill rotary speed should be, this way can protect the centre bit from getting snapped.