Boss 393 Gutter-Seal is a new VOC compliant sealant in all 50 states. Boss 393 Gutter-Seal was designed without the harsh smells of solvents, it's non-flammable, with no shrinking. Boss 393 Gutter-Seal is fast curing and provides permanent elastic adhesion to most surfaces. Boss 393 Gutter-Seal is recommended for sealing all types of gutters, downspouts, ducts and ventilators. Boss 393 Gutter-Seal is excellent for sealing seams, joints and cracks in gutter troughs, HVAC ducts and sheet metal. It cures on exposure to atmospheric moisture to form a durable flexible watertight seal. Boss 393 Gutter-Seal can be applied and tooled in most weather conditions (-35 degrees Fahrenheit to 140 degrees Fahrenheit), maintains adhesion and will not crack.