DESCRIPTION Bostik DUO-SIL is a special formulation of urethane and acrylic emulsion formulated for the professional applicator which can be used as an adhesive or caulking compound for commercial and residential construction. DUO-SIL as a caulking compound can be used to fill butt joints in vinyl, aluminum and fiber cement siding, windows, doors, bricks, counter tops, and most areas where a sealant is needed. DUO-SIL as an adhesive has superior bond to most building substrates with no need for primer. DUO-SIL will adhere to wood, metal, gypsum board, vinyl board, cove base, foam board and many more building products. DUO-SIL as an adhesive and caulking compound will not affect Polystyrene foam bead board the way most solvent based or plasticized sealants do.