How to know if I have an automatic changeover on my tanks.

We had one on our old TT that was a bit different. If you flipped it to point at one tank or the other it would only draw from that tank. If you set it in the center it would draw from both, which isn't an auto switch it just basically has both open. Our current one doesn't seem to have an auto as one day when the tank went dry my grill shut off. The one I have looks like this but this says it is auto. http://www.campingworld.com/shopping/item/propane-auto-changeover-two-stage-regulator/24030