The DS1 Oil-Based Duct Seal Compound fills irregular openings to protect from air, dust, or water while providing vibration dampening properties. The non-hardening sealant adheres to metal, masonry, wood, and plastic. Duct seal is non-corrosive, non-toxic, contains no asbestos, and will not stain or harm the user's hands. Safe and easy to use with no unpleasant odor. Maximum temperature rating of 210°F (99°C). Dielectric Strength 200 (V/Mil). Color Dark Gray/Green. 1 lb package.