Best Plumbing or Drainage System or Product

Each entry in this category should be for a single product that the entrant believes is the best on the market. This could be because it is better designed/manufactured, or simply deserves to be the de-facto choice for self builders. The product can be anything from innovative radiators to rainwater harvesting systems, shower fittings or underfloor heating pipework.

Details of the product are required, ideally with images of it installed in a home.