The Poth-O-CarryOriginal: Rail Edition was designed to hold Pothos (and other plants) at the top of your fish tank, with the bottom of their stalk dipped in, the leafy part on top. An adjustable rail lets you slide the Poth-O-Carryup and down almost 6\”, great for tanks with lower water like ripariums. Sometimes a suction cup is fine, but let\’s face it, suction cups… suck. They aways fall off, and you periodically need to reaffix them. With Poth-O-CarryRail Edition, you never need worry. The plant will drink in the delicious fertilized water from your fish tank and thrive! As a thank you, the plant will slurp up the excess nitrate in your tank, decreasing the frequency of water changes required. It\’s a total win-win. Pothos also has the added benefit of absorbing airborne toxins in your home! Pretty cool. The Poth-O-Carry, while originally designed for pothos, will also hold other plants, including lucky bamboo, spider plants, wandering jew, orchids, etc. Basically, if it thrives in an aquaponic environment, and fits down the tube, you\’re in. Some plants do better at nitrate absorption than others, but sometimes ya just want pretty flowers or something. well that\’s just fine with Poth-O-Carry. It needs less than 4\” space on your tankside.