I think, don't quote me on this because this is off the top of my head. I think I got mine from Don's Hobby Shop. You can go direct to www.fromeco.org and cut out the middle man. This tach is so good I can stand five feet behind the aircraft and get A perfect reading.
Eric, I tested my friends H-9 tach/volt one day against mine. The reason was we couldn't get A reading from his at all at the field that was even close to the same from time to time. We found out that under different light conditions and back grounds his tach just wouldn't read. All we had was direct over head sun. Once we got the plane at home and in the shade with some background the H-9 unit was dead on. It just didn't like the desert sun we had that day. Out of the different makes of tachs I have tried the H-9 is one of the better ones and that volt meter comes in handy.