You can't seal your horse in a fly-free zone, but Endure Sweat-Resistant Fly Roll On for Horses is the next-best option. Its unique formula keeps on working - even in wet conditions such as sweat and rain. Protect your horse from biting and nuisance flies, gnats and deer ticks that may transmit Lyme disease. Provides up to 14 days fly control. The only fly product with RepeLock conditioner, which binds to the hair shaft. Contains Cypermethrin, Pyrethrins, Piperonyl Butoxide, and Butoxypolypropylene Glycol.