An Effective Fly Spray That Won't Sweat Off! Stays active and keeps working, even in wet conditions Provides up to 14 days fly control RepeLock conditioner binds to the hair shaft and won't sweat off Protects against biting and nuisance flies, gnats, deer ticks and lice Provides repellency and quick knockdown of mosquitoes The only fly spray with RepeLock formulation. RepeLock formulation is an exclusive conditioner that binds to the hair shaft, locking in the fly repellency of Endure fly spray. This unique formula stays active even when your horse sweats or in wet conditions.