Pond filter box with 3 sponges and net bag for stones or filter material just put your pump with the filter box in the pond when the sun shines and the battery is fully charged the water flows from the top down through the single sponges and net bag filled with stones or filter material to the pump the filtered pond water is transported back the pond via the sprinkler you will receive filter box made of black plastic 3 filter sponges 2 net bags for filter stones or filter material