TST Orange Power Drop-Ins take the guesswork out of RV or marine holding tank treatment. No measuring, no mess. Just add one Drop-In to treat a 40 gallon tank. Harness the power of citrus to stop odors and break down waste. Fresh citrus scent. Contains 15 treatments. Environmentally safe. - Fresh citrus scent - Drop packet into your RV toilet to break down waste and tissue and treat both black and grey water tanks - Stops odors for up to 7 days - Contains 15 treatments - Environmentally friendly safe for septic tanks