Review on Pawfly Cross Aquarium Gang Valve: Efficient Air Flow Control Lever Valve with Check Valves, Suction Cups & Connectors for Fish Tank by Sandra Goode

Great little collector. It's a little tricky to get a precise tiny drop of bubbles out of my decorative volcano. However, it masters its task properly, the supplied suction cups only hold it to the side of the aquarium. The standard air hose fits perfectly. One problem: Three one-way valves didn't work, none of them. The air blew easily in every direction so they didn't prevent the back flow of water. There isn't much of a problem here since collapsible check valves are cheap.