Max Control Holding Tank Deodorant - Four (4) Pack of 8oz BottlesMax Control Advanced formaldehyde-free formula. Long lasting treatment eliminates and controls holding tank odors by breaking down waste and toilet tissue. Features:. 4 ounces treats a 40 gallon holding tank. Formaldehyde-Free Formula. Easy to use. See-through window stripe for measuring ease. Eight (8) oz. Container. New Item # 9108557759 *Sold by the four (4) Pack