Z-itch is a ready to use, pour-on solution for the control of sweet itch on horses and donkeys. This product may be used as an aid in the control of the biting insect Culicoides spp. Z-itch should be applied weekly at the start of the itch season. It is supplied in an easy to use pour on solution.Long lasting and effective. Contains permethrin 40mg/ml. Legal Category: AVM-GSL.