Keep your black tank fresh and clean with Camco's TST MAX Citrus Drop-INs. These Drop-INs are specially designed to eliminate odors, break down waste, and ensure top performance in RV and marine tanks. TST Max RV toilet pods are designed to be safe for your septic tank and the environment. The ultra-concentrated formula offers a sustainable solution for your toilet treatment needs. Convenient and powerful, each Drop-IN treats up to a 40-gallon tank for seven days of odor prevention with just one application.