Duct Seal

In stock

Hardcast Duct-Seal 321 Gray is an industrial-grade, water-based duct sealant designed for metal ducts, fiberglass duct board, and flexible duct systems. It features built-in fiber reinforcement and UV inhibitors for indoor and outdoor applications. The sealant provides a durable, airtight seal and meets UL 181B-M requirements for HVAC systems.

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