There are two types of paint rollers: 1. 9? frames 2. 4? frames The large roller of 9 inch is better for wall painting while the 4 inch style is apt for enamel paints on wood but it is also true that we should go for foam based small roller frames for gloss finish washable wall paints. Always buy the good quality rollers which will last much longer and give you superb finish. Handle of a roller plays vital role in painting because if you are doing a lot of painting worj, a roller frame with a comfort grip will keep your hand from cramping. We should always use roller gently with light pressure & clean up after using wall, metal or wood paint. For the foam based roller, hold the roller cover under running water and squeeze your hand over the roller to remove the paint. Repeat until all the paint is out of the roller, then let dry. Never leave the cover soaking in water & if it is used in enamel paint, leave it turpentine oil.