Fenwicks Waste Pipe and Tank Clean is a one shot interior cleaning agent for your caravan or motor home. Used neat it unblocks blocked drains, cleans grey and black water systems including convoluted hoses killing germs. Dilute to a 10:1 solution to clean work surfaces, cookers, fridges, sinks, wash basins showers and toilets. Fully biodegradable and food safe. Also removes nicotine, egg, limescale, formaldehyde and other hard to remove stains. Excellent all round value for money cleaner. 1 Litre.