Using Fleetwood Traditional Undercoat - 750ml + 33% Extra Free under your paint ensures a smoother, more durable finish, and more protection to prevent your topcoat from peeling. This undercoat is an excellent choice for interior and exterior wood and metal. It is also recommended to apply an undercoat if you are changing the type of paint you are using; for example oil based paint over acrylic. This high quality undercoat brings you the added benefit of being dirt and stain resistant. With this great promotional pack you get 1 litre for the price of just 750ml.