Material:TCT Hole Saw. Available materials: thick cast iron, thick steel plate, abrasive steel, stainless steel, thick non-standard iron, aluminum alloy, aluminum plate and other non-standard metals (all kinds of wood, density board, compressed version). Not recommended: concrete, stone, ceramic tile, glass. Sizes: 12 – 200 mm. Compatible equipment: electric drill, bench drill. The power of hand drill must be greater than 750W. Prohibit the use of impact drills. For specifications below 50mm, the shank diameter is 10mm. For specifications of 50mm and above, the shank is 12mm. When manufacturing parts, to make them interchangeable, the parts should be within the specified maximum and minimum limits. The permissible size variation is: tolerance, but they all fall within the scope of the industry regulations. Contact online customer service for information on specific tolerances. When the product is ordered, the tolerance is accepted by default. According to your Choose! Terms of sales. If you are not satisfied with the item, please contact with us. Any problem, please feel free to contact with us. We care about our valued buyers, if you have any questions, our Customer Service staffs will be very glad to help you. We try our best to reply to your emails as soon as possible, however, due to high volume of daily incoming emails and time zone difference, we may not be able to reply your emails immediately. About item:For the functional products in our shop, we make sure that the functions are the same as description, but the actual color and shape may looks a little different from pictures because of the technical improvement and manufacturing variance.