I have a ColloidalSilverGens CS110 but this company is being sold, don't know who to or why. If I had to buy one now, I would get a SilverGen SG6 Auto or a Silverpuppy, both have constant current, stirrers and auto shut off. If you buy one without a stirrer, you can buy a cheap aquarium bubbler to stir the solution, this helps control current and keep particles small.