V4 Z Bond V4 is a one component, non-flowing, neutral cure, low modulus silicone sealant, forming a flexible and durable elastomeric sealant. Because of its good adhesion to a broad range of substrates and low modulus, this product is an excellent general-purpose building and construction sealant. It is commonly used in weather seals in curtain wall; air seal in pre-cast concrete; sealing of Marble & Granite (after the completion of stain testing); sealing polycarbonate.