Star Brite Instant Fresh Toilet CleanerHighly effective way to deal with the boat's holding tank that eliminates the need for multiple chemicals• Non-formaldehyde, non-staining, biodegradable formula.• Latest technological lubricants keep drain valves from sticking.• Breaks down waste quickly and efficiently.• One ounce treats five gallons.• Fresh pine scent controls holding tank odors fresh lemon scent controls holding tank odors.• Complies with EU criteria for biodegradable products;• contains lubricants that prevent drain valves from sticking