The Tradition roller cover is a high quality woven fabric sleeve that is suitable for all paints for both interior and exterior painting. This roller cover will ensure a smooth finish and is lint free. For greater paint pick-up and release, choose a roller with a longer nap (longer fibres). For a smoother finish, choose a roller with a shorter nap. The 5mm roller refill is best suited for very smooth surfaces such as unpainted walls, metal, smooth ceilings, smooth plaster, smooth wooden surfaces and trim. Use a 5mm roller refill when using high-gloss paints for a super-smooth finish.