For testing air movement ducts such as flues & chimneys. Can also be useful in testing drainage pipes & tightness testing Plastic coated pellets for ease of handling Each pellet burns for Approx. 30 seconds Each pellet releases Approx. 7 cubic metres of smoke Gives off a white smoke to determine the air flow Non-toxic, non-acidic & non-explosive Encapsulated smoke pellets making them easier to handle