A couple of years ago I had a tachometer to go bad. No luck in repairing. so I bought 2 new ones - digital (and they weren't cheap!). This left me with a left over serviceable one (see pic). As far as I know it still works. No idea how much life is left in it. YOU PAY FOR SHIPPING AND IT'S YOURS! That's all, nothing more. (Hope the pic works)
