Hi, Just make your own. My battery charger is a Shumacher BatteryMaintainer that has a 12V and a 6V option for $12 on Amazon. That is what you'll need and then you can experiment with either the homemade plates or two metal prongs of some type such as spoons or heavy detached stainless steel pot handles. You don't need to do the fancy plates because the spoons work just as well. As long as you see the bubbling between the spoons then you've got everything working fine.
Other instructions: have hot water to above the ankles in any old plastic bucket or tub, add 1/4tsp Sea Salt , and then put the charger clamps onto the top of the two metal prongs/spoons, put the two metal prongs/spoons close together until bubbling in the water begins to occur. Don't forget to drink plenty of clean fresh water before and after, even during the session, and also take minerals after the footbath for instance terramin clay or other mineral supplement following your detox session. Save your money.