Sun has been around for a very long time, too, and they make a very nice looking tach.
As Stuart says, 6v is pretty slim pickings, but they can be found on ebay if you're patient. They usually run about $30-$80 for the transmitter and $20-$70 for the gauge, depending on the number of lobes and the voltage.
If you don't want to wait, give
Williamson\'s a call and tell them what application you have and ask what they've got that'll work. Many bolters have used them and like their work. I'm thinking about sending my old Sun Brainbox to them for the solid-state conversion.
