Very sturdy smooth spiral rubber hose used to connect the boat toilet drain pipe. It prevent smells due to the draining function of toilets.
The material used has a smooth inside surface featuring non-sticking and anti-smell properties, it's resistant to the growth of bacterial flora, to acids and bases, and has a low chafing rate and low permeability.
Also used to connect biological tanks, biological pumps and bilge pumps on pleasure boats.