Smooth rolling but they have no seal so minor debris like a small grain of sand makes them jam up. I will need to replace them with something less susceptible to dirt. Sucks because they work perfectly when they roll. Right now we have to carefully clean the material we put on the machine feeder. We used to use guide blocks with oiled leather pads. I'm starting to think about going back to them. They were less trouble. In summary - good bearing just not for my application.
no seal 
