The Merck Animal Health Ultra Saber Pour-On Insecticide is a fast acting, long lasting fly repellent. Take Saber pour-on's active ingredient - Lambdacyhalothrin- add a synergist, piperonyl butoxide (PBO), and you get ULTRA SABER - a powerful new force in controlling profit-robbing horn flies. The pyrethrin spray-alternative disarms horse flies' ability to break down Lambdacyhalothrin, which increases the activity of the insecticide. This enhanced insecticidal activation of synergized Lambdacyhalothrin allows quick knockdown and extended duration of efficacy against horn flies. The pour-on insecticide helps kill more horn flies faster and longer in order to limit the stress they cause cattle and the associated economic losses they cause producers. Horn flies bleed profits. Horn flies pierce cattle's skin and suck blood up to 40 times per day. The results bleed producers' profits, with millions of dollars lost annually.Note: This product may require up to 2 additional days for order processing prior to shipping