Never heard of them until recently. But these tanks come in different sizes and can be slid through a doorway. They come in 100 to 750 gallon size and fit out of the way. I bought a 300 gal tank which sits just outside my carport entry door. I have a well, a swimming pool and several 5 gal jugs as emergency water sources, but having 300 gals of clean water that I don't have to exit the house for is a plus. I would recommend these as emergency backup storage for water. Lockes carry them. You will need a sturdy floor to set them on though. I do believe I will order another one to put on my patio under a cover and out of sight.