Easily convert your standard aquarium into a reef-ready tank with the acrylic Seapora Nano Overflow Box! It features a hang-on-tank design, and incorporates a foam cylinder, nylon tube, screw and 0.75" bulkhead. Achieve excellent water quality for a thriving environment. This Overflow is ideal for beginners or hobbyists and is suitable for use on smaller tanks up to 30 gallons.