Todd's one piece molded Water and Holding Tanks are tough and durable. Each tank fully complies with FDA regulation CFR 177.1520. Each tank satisfies all United States Coast Guard standards. SURPASS material tanks will not emit waste odors or change the taste of fresh potable water. All openings are female NPT (National Pipe Threads) and are located in the same relative position on one end of the tank. Supplied Plugs make Water Tank or Holding Tanks complete, instructions included.