Sikaflex-521 UV is a multi-purpose non-sag elastic one-part sealant based on a polyurethane-hybrid compound, which cures on exposure to atmospheric moisture to form a durable elastomer. Use Sikaflex-521 UV adheres well to a wide variety of substrates and is suitable for elastic sealing and bonding. Suitable substrate materials are timber, metals, metal primers and paint coatings (two-part systems), ceramic materials and plastics. Characteristics and Advantages 1-C hybrid formulation Elastic Ageing and weather resistant Bonds well to a wide variety of substrates without the need for special pre-treatment Can be overpainted Can be sanded Low odour Non-corrosive High electrical resistance VOC and solvent-free - silicone free - PVC free Colour Grey, White, Black Packaging 300ml Cartridge - Grey & White 600ml Sausage - Black, Grey & White.