I bought this for one time use to drill a round hole in a stacked rock I placed in a fireplace remodel. The holes were for cables. It took me a while to get through an inch of rock and I wet my head about every 30 seconds to keep dust and heat under control. Basically had a bowl of water, dunked it and kept drilling. It worked. Do-it-yourself guys is a good product. Pros know what to take and it's not their choice. All I needed was a disposable and affordable bit and it worked.