Cavalor FlyLess is a powerful insect repellent that gives horses and riders protection against flies, horse-flies, mosquitoes, ticks, and other insects. Pleasantly scented so you can enjoy your summer rides to the fullest. Cavalor FlyLess contains icaridin (20.6%). Icaridin acts as a blanket of fragrance on the skin, disrupting the mechanism that attracts insects to humans and animals. Studies have shown that formulas with 20% icaridin protect people for up to 10 hours and horses for even up to 24 hours. Icaridin does not kill insects, so there is no risk of resistance.