I am currently building custom sized polycarbonate generators. I build them as the request comes in, so I dont have stocked units. Generally the units will run from $140 to $220. Price depends on size and amount of plates. These units are a bit large and hold a gallon or more of electrolyte. I have posted photos of a single cell unit and a double cell unit. The single cell produces .7 LPM at about 7 amps and the double cell I havent been able to measure yet, but it produces very well at 9 amps as you can see by the picture. The unit ran for 3 hours and the temp only reached 122°. The other photo is of a bubbler. It measures 2 X 2 X 6 inches. You can PM me in these boards, or email me at rjmarb1@suddenlink.net