When I tried this Industrial and Scientific accessory, I couldn't believe how much easier it made my job! These plastic mandrels are perfect for installing hole saws and the drilling process was a breeze... The quality is great, AND they fit the hole saws perfectly. The only downside is that they are made of plastic, so they may not hold up as well under heavy use. Overall, I highly recommend this product to anyone in need of a reliable and easy-to-use accessory for cutting holes..