This is a used Hozelock Bioforce Revolution pressurised filter system. It can handle up to 9000 litres of water per hour and is suitable for koi stocked ponds up to 4,500 litres or fish stocked ponds up to 9,000 litres. It contains a 24w ultraviolet steriliser as well as mechanical and biological media. I have just removed it from my pond as it is not large enough to filter the volume. It is in full working order but may require a new UV bulb. It comes with 3m of cable and can be installed near the pond with a suitable hose to return the water to the pond. It also has a in-built cleaning function with a external outlet to remove dirty water.