You could always make your own if you like. I have me plans for a couple of machines but gave up on the idea of silver due to it's poor results and bacteria finding ways to neutralize it. There is the SilverMax schematic with circuit board and other stuff, I do not know whether it is still available online. I did not like the relatively low voltage it starts with which if I remember correctly was 12 volts. I have the schematic on my hard drive but you might be able to find it by searching for SilverMax.
The other created by Scott Claussen, which I prefer, uses a much higher voltage ie 36 to 40 volts which is around what I was using > 38V. It also offers better current adjustment, keeping it at a more ideal level ie 1ma/inch^2 of silver surface area. It does offer a decent adjustment range of 0.51430 milliamps to 5.4200 milliamps with another option for additional adjustment with a set point. There is a parts list and circuit diagram in the manual which is available on the site. It has a GNU Free Documentation License. He did have a website where I got it from but it is no longer online unless it could be accessed via the wayback machine.
Yep here it is and might be worth a look. It looks like it went offline sometime after May 2018>
BTW There was a document available about CS and the different CS makers created by grizz on this forum. I cannot find it ATM, I seem to remember I had it bookmarked somewhere. You might be able to find a link somewhere on this forum section in grizz's postings, maybe in the links. It was quite comprehensive.