Smooth surface, but clay doesn't stick to it, which is great. It is a little slippery, though, and feels like it could be another 2 inches long or so. I was using a sawed-off wooden dowel, so it's definitely an improvement. But mysteriously, hairline cracks developed throughout the roller. It doesn't appear to impact the fuctionality, but it did concern me. It appears to scratch easily, so if you have other clay tools lying around, they may mark into it.