Meeco MEFireEx FireEx 5" x 5" Bag Chimney Fire SuppressantStops Chimney Fires Quickly. Safe and easy to use; simply toss entire package into the firebox. NOT A FLARE; no pre ignition required. Performance tested by Lokee Testing Laboratory using creosote fueled chimney fires. No water damage. For wood stoves, fireplace inserts and fireplaces. 5x5 bag inside box Toss product into active fire, A white zinc oxide cloud will suffocate the fire flames once product begins its chemical reaction, close door. Product