According to my experience this hole saw is a complete waste of money.The teeth dulled quickly, despite careful use, and the saw blade BENT after only a few uses. The carbide tip seemed to be of low quality, and the product was not up to the standard of other cutting tools I've used. The only positive aspect was the relatively low price compared to other hole saws on the market. Save your money and invest in a higher quality product for your industrial and scientific needs..