The TST MAX Drop-Ins help control unwanted odors and break down waste and tissue in your black water holding tank. The easy-to-use drop-ins contain a special chemical that helps break down waste. They also have a blend of ocean-scented surfactant oils that trap unwanted odors in your tank, making your camping experience more enjoyable. The drop-ins are RV and marine approved, non-formaldehyde, and safe for all septic tanks. They're even great for portable camping toilets. Each container comes with 30 drop-ins.• Eliminates odors and breaks down waste in RV black water holding tanks• Ultra-concentrated formula• Just one drop-in treats up to 40 gallons• Does not contain toxic, formaldehyde-releasing bronopol• 100% biodegradable and safe for all septic tanks• 30 drop-ins per container Ocean-scented oils trap unwanted odors 100% biodegradable & safe for all septic tanks 30 drop-ins per container | Camco TST MAX Ocean Scent Drop-Ins, 30-Pack in Black