Size 1590 x 510 x 630mm. Suitable for Koi ponds up to 1,750 gallons (7875 litres), or Goldfish ponds up to 3,500 gallons (15,750 litres). This 3 Bay unit comprises of a first stage vortex bay, with Bay 2 being fitted with mechanical brushes, and Bay 3 serving as the main biological/mechanical stage - incorporating foam and the highly proclaimed aqua rock/alfagrog. Again this unit would also be very useful if fed from a skimmer unit on a larger pond. Note:- Pipe inlet size 110mm (4") - Outlet 82mm (3").