Always refer to the manufacturer's instructions to confirm the recommended roller cover. Typically, the recommended nap thickness ranges from 3/16" to 3/8". When applying solvent- or oil-based paint, be sure to use solvent-safe roller covers. Foam rollers tend to leave the smoothest finish. Mighty Mini rollers have a 3/8" nap and work well with TotalBoat antifouling paints. Foam rollers with a 1/8" nap are another good option.