Camco's TST MAX Lavender RV Toilet Treatment Drop-INs help control unwanted odors and break down waste and tissue in your RV or marine waste holding tank. Just (1) Drop-IN treats up to a 40-gallon tank and stops odors for up to 7 days. This product is RV and marine approved and is completely biodegradable. It does not contain formaldehyde, pesticides or biocides and is safe for all septic tanks. It's even great for portable camping toilets! Includes (15) lavender-scented Drop-INs. Made proudly in the USA.