Ray-JrMALL 3Pcs Bio Sponge Filter for Aquarium Fish Tank Shrimp Mini shape, does not hold the volume and beautiful; using planarians, leeches activity habits, bottom import, in order to strengthen the trapping effect, while the nozzle is small, so that the planarians easily get in and hardly get out to achieve trapping purposes. Material: plastic. Color: transparent. Size: diameter 3.7 x height 4.8 cm.