S'top Fly by Greenpex is a care product that protects all equines against ectoparasites (flies, flatflies, horseflies, mosquitoes, etc.) with an effectiveness of 4 weeks. The active ingredients of natural origin are gradually released on the surface of the collar and form a repellent halo around the animal's body. This protection also helps reduce the risk of summer dermatitis in predisposed subjects. The qualities of the collar are not altered by rain or perspiration.