One thing to remember is there have been more than two iterations of the F-1, there was the original F1, the F1n and the New F1. Check here for the models and there specs. . I have had a new F1 for several years now and love it, built like a tank. The first two DO use a mercury battery, but Freestyle has a Wein replacement for it - Dad use's one of these on his FTB and they work just fine. Good luck