The TST lemon holding tank treatment helps control unwanted odors in your black water holding tank. The easy to use liquid contains a blend of lemon-scented surfactant oils that trap unwanted odors in your tank, making your camping experience more enjoyable. Test lemon is RV and marine approved, non-formaldehyde and safe for All septic tanks-it's even great for portable camping toilets 4 oz bottle 8/pack. New lemon scent Eliminates odors and helps break down waste in the RV Holding tank 8 pack of 4 oz bottles RV and marine approved; safe for all septic tanks Environmentally safe non-formaldehyde formula MODEL NO - 41571