FireEx protects your home from chimney fires. Smothers chimney fires safely and quickly. Nothing to light - simply throw the entire package onto a burning fire. Try to eliminate any drafts by either closing doors or covering opening with fire retardant material. For use in wood stoves and fireplaces. Safe, fast, and dependable. Some larger stoves and fireplaces may require 2 packs. Zinc oxide compound. Packaged in airtight plastic for indefinite shelf life and no chance of water damage.