Accuair 4-Way Aquarium Gang Valve

I use it as a three way splitter with the fourth connection open. This allows me to use the fourth position to control the sound of the air pump by minimzing back pressure in the air line (just let it bleed into the room). When I left the 4th closed and the other 3 throttled to set the air flow on each of the three, the air pump was fairly loud because of the pressure built up in the airline. Opening the valve on the 4th (unused) connection relieved the pressure to keep to pump quiet.

My one complaint is the flexibility of the barb on which the airline slides onto. The airline itself (I used standard aquarium airline) is firmer than the barb on this gang valve so it was a bit of a pain to slide the airline onto the flimsy barb.