Hartz® OneSpot® Fle Egg & Flea Larvae Treatment for Cats & Kittens. Ultra Guard®. Controls & prevents: Flea eggs and flea larvae for 30 days. Breaks the flea life cycle. 3 Month supply. Net contents: Contains 3 tubes, each 0.03 fl. oz. (1 ml). Prevents re-infestation for 1 month. EPA Reg. No. 2596-147. EPA Est. No. 2596-OH-1. Hartz® and other trademarks are trademarks of the Hartz Mountain Corporation. For more information, Call our experts at 1-800-275-1414.