The Bestway filter pump comes with two pipes that are connected to the pool in two different places. The water is pumped out of the pool and cleaned by the filter cartridge and pumped back again. For optimal operation, the filter cartridge (depending on the contamination of the water) must be cleaned/flushed or replaced regularly The pool connections have a diameter of 32 and 38 mm. filter cartridge III-A/C included Suitable for swimming pools from 1100-31700 litres