RYOT4 EXPRIME is water based Exterior Wall Primer suitable for application on exteriors as an undercoat to exterior emulsions paint. Its innovative technology delivers excellent adhesion, durability, sealing, fast drying, spreading rates, opacity, whiteness and algae –fungus resistant. Properties. Its latest pigment technology ensures excellent weather resistance and outdoor durability, It Improves appearance of top coat, Does not chalk and can be applied on adequately cured fresh plaster .It Does not require curing with water