MC-1230 ( U solder Kit) the popular MC-12 was 86ed to bring you the new improved MC-1230. We sell it all soldered up and tested for $125.00 or the U solder it yourself kit. It has the same 555 timer & comparator chips to make the square wave pulse. Now has 2 mosfets and fan to keep it cool all the time, it is needed in the hot summer months, in the winter the fan can be disconnected. Brass mounted screws right to the pcb board for a good connection. What is in the photo is what you get. Complete down loadable instructions. *Note : We have new instructions for the 2/12 model, same effects as the older versions. Parts in photo are slightly different. This PWM is rugged for HHO applications. Some say the best square wave pulser they have found.