OSI HM270 Construction Silicone Sealant is a medium modulus, one-part RTV silicone sealant designed for glazing and sealing. It cures at room temperature upon exposure to moisture in the air providing good tensile strength and excellent adhesion, usually without the use of a primer, to most nonporous building materials. OSI HM270 easily withstands temperature extremes from -60°F to 400°F without adverse effects. It is highly resistant to ultraviolet light and is virtually unaffected by other harsh environmental elements. OSI HM270 offers superior elasticity and long-life reliability. It forms a permanent watertight and weatherproof bond to materials like glass, ceramics, aluminum, primed steel and some plastics.