As best described in Grinding Wheels and Abrasive Wheels
Works well on a surface you don't want to sand aggressively. I've only used it on a sealing surface, can't tell how it would work on anything else.
Pros
. Size details: bristle disc diameter is 2 inch/50 mm, round shaft diameter is 1/4 inch/6.35 mm, overall length is 2.6 inch/65 mm, size fits, easy to use and store. Doesn't take up much space