It's only open on one side. Instead of having a "closed" setting, it has one hole, smaller than the next one hole setting. I purchased it online about a month and a half ago? I honestly don't remember where I got it from since I've ordered so much stuff from so many different places. I just checked the ID code online at the Kangertech website and it did confirm that it is an authentic tank.The first one (with a "closed" setting) sounds right, but the new one should be "small hole, large hole, wide open slot" with only three settings, and each one is open on both sides instead of just the one side. I've never heard of a "small hole" version with all four settings. Is it open on both sides or just the one? Where did you get it from? And how long have you had it?