We have had such good results with this simple design in our 2500 gallon IBC aquaponics system since 2012 that we are proud to make them available here on . Our siphons use the "Affnan" 2-1 funnel top design that assures an amazingly fast start and no we do not ever use a "trap" at the bottom because traps clog up down the road and cause failures. We also do not use the small "snorkel tube" you may see on other bells as that too gets clogged or breaks seal and we find it totally unnecessary (and very noisy) with our design which allows air to come under the bell and back up the down tube when it comes time to "break siphon". Simple and always trouble free with guaranteed reliable starts and stops. Also, we use a 4" gravel/media guard TO SAVE YOU GROW SPACE and they are easy to rotate in place to cut off any roots that are always trying to grow through any gravel guard. We rotate ours about once a month and that is pretty much ALL the maintenance these siphons ever need. Those 6" guards are unnecessary, expensive to ship and take up way too much of your valuable grow space. Our guards are made of S&D 200lbs per square inch pipe that boasts a larger inner diameter than schedule 40 for bigger hands like mine. Our bells have a porcelain knob held on with a stainless steel screw for easy maintenance (will last forever) or just for having a quick look. These are the prettiest, best working, "easy to adjust the water level" bell siphons anywhere. The only ones voted even better looking by our visitors are our "Clear Top" bells that we also offer for a bit more money. Kids love watching them work as well. The only thing kids love more is watching the fish. We have built and shipped over 1000 bell siphons so buy with confidence. You get everything you see in the main photo including the 2 adjuster rings. A complete bell siphon ready to go in your 12" deep IBC media bed.