This is an Automatic Egg Collector for CPDs and other egg scatterers. It can be used two different ways- stand alone or hooked up to a Fluval Breeder Box (not included). To use as the stand alone version, an egg basket is included to catch the eggs. For the Fluval version, an adapter is included to connect the breeder box to the collector's lift tube. To collect the eggs, place a bit of moss on top of the collector box and pin it down with the included moss peg. An air valve is included so that you can control the rate of air flow to the lift tube.The lift tube sucks water and eggs from the grate under the moss. It also sucks in everything else that comes out of a fish, so you will want to clean it fairly regularly.