Kills by contact. Kills for up to 4 weeks (Against mosquitoes and houseflies on non-porous surfaces). Kills houseflies, mosquitoes & other listed insects. Water based. Guaranteed! to work, or your money back (For terms of guarantee, see back). Guaranteed! If you are not satisfied with this product for any reasons, 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. www.hotshot.com. Questions or Comments? Call 1-800-917-5431 or visit our website at www.hotshot.com. Contains No CFCs or other ozone depleting substances. Federal regulations prohibit CFC propellants in aerosols.