Happy Horse 14-Day Fly Spray is a ready to use 1% Cyper. Horse Spray Repellent formula that provides repellency and quick knockdown from flies, gnats and mosquitoes. The spray gives up to 14 days fly control and provides repellency and long lasting protection from: Horseflies, Houseflies, Stableflies, Faceflies, Hornflies, Deerflies, Gnats, Mosquitoes (Culex spp.). The unique formulation stays active and keeps working even when the horse sweats, and after rainfall.