To start with let me just say that I have been taking 10PPM colloidal silver for over 25 years now and to my best recollection have not had a cold or the flu after about 6 months dosing @ 2 shots/day. I will be 68 this year, I take no meds, I still ride motorcycles, I windsurf, and I raise Mustangs for fun. (and no I am not blue) I have been using an older Silver Gen model from Washington State for the last 15 years. This model uses the 1 x 6 inch electrodes and will produce very clean 10ppm CS at the rate of 1 liter/hour. I could not find this style anywhere and must assume the company is out of business or the founder has passed away. What I did find when I tried to locate a user friendly device on the web for one of my friends was the huge increase in selection of CS systems. It took me almost 3 hours to wade through them all and decide on one model that was; 1 User friendly, 2 Economical, 3 Constant Current, and 4 Backed by good service and replacement parts. This is why I chose the Colloid Master AC colloidal Silver Maker @ $144.00usd. I also opted for the TDS – PPM turbidity tester for determining parts per million. The package arrived on time and everything advertised was present and functioned perfectly. I grabbed the first narrow mouth Mason jar in the cabinet and found it to hold 1 liter exactly. This volume produced 10-11 ppm in about 3 hours repeatedly. We also found the TDS PPM turbidity meter to function well and was very easy to use. I particularly like the one minute switching of the electrode polarity to keep the wear even. I had to mark my older unit and remember what polarity I used last in order to balance the wear. My older unit did not have a built in timer and I always had to use a countdown timer for consistency. The automatic cut off on the new unit worked perfectly and made the longer production time seem insignificant. All said, I felt like I made the best choice given the selections and will soon order a new one to replace my old unit when I am not in a hurry or don’t need to make large 1 Gallon + batches. I would recommend this model to any newcomer to CS manufacturing. Good health, James Stevens Texas USA 02/08/2016