Guaranteed to work or your money back (For terms of guarantee, see back). Kill fast. Keeps killing up to 4 weeks. Use indoors & outdoors. Black Flag Flying Insect Killer kills fast plus kills insects landing on treated surfaces for up to 4 weeks. Questions or comments? Call 1-800-887-3524 or visit our website at www.blackflag.com. Guarantee. If you are not satisfied with this product for any reason, send your written request for a refund to the address below, together with the dated store receipt showing the price you paid. Please allow 6-8 weeks for processing. Contains no CFCs or other ozone depleting substances. Federal regulations prohibit CFC propellants in aerosols. For use around the home only.