Low modulus neutral cure silicone. Eliminates the need for grouting. Long life. Adhesion to most building materials - all types of lead (BS:EN 12588 (1999) compatible, milled, rolled, sand cast, water-cooled), other metals, brickwork, concrete, granite, marble, slate, cement, stone and roofing tiles. Lead grey colouring. Non-corrosive. Good UV and weather resistance. Forms a watertight and permanently flexible joint.