Useful when the roller is better than brush with small area paint. The price is also cheap and easy to wash and can be used repeatedly. Also, in case of solvent type, thinner will be saved if you wipe it early with cloth etc etc. I would like to have a groove on the corner to transfer the excess paint to the container if possible.
Usability is normal. It is easy to wash and can be used repeatedly. I wonder if it's ok if you do not buy it for the time being. For washing, it is convenient to use Kao's "Magic Ring Pikachi Shining Sheet".