Hartz® First Defense™ Topical Treatment for Dogs 23-44lbs. Contains Fipronil, the Active Ingredient used in Frontline® Top spot®. Kills fleas, ticks, chewing lice. Prevents and controls re-infestation. Fast acting. Long lasting. Waterproof. Hartz® First Defense™ is not manufactured by or distributed by Merial. Frontline® Top Spot® is a registered trademarks of Merial. Net contents: 0.135 fl oz (4.02 ml). For more information call our experts at 1-800-275-1414. Hartz® and other trademarks are trademarks of The Hartz Mountain Corporation.