I bought this one (http://www.amazon.com/ActiveAqua-Ft-Flexible-Air-Stone/dp/B002ZXHBVQ/ref=sr_1_26?ie=UTF8&qid=1335384828&sr=8-26) and it actually has 2 inlets, one on each side, plug in 2 lines one on each side and that air stone will produce some pretty mean bubbles man. Also this one comes...