NuFlex¨ 309 Metal & Vinyl Silicone Sealant is a one-part, neutral-cure elastomeric silicone sealant that cures to form a durable, flexible, low modulus sealant that is compatible with common building materials. Ideal for sealing or bonding any combination of masonry, ceramics, galvanized steel and aluminum substrates. Available in grey, natural stone or white. Comes in a 10.2 oz tube that fits most standard caulking guns.