I'm hoping that my Ping Buddy will last "forever" -- I just can't imagine why uAvionix stopped making and providing them for "us"...works flawlessly with my 740b! (which also works flawlessly, I might add!). I did see a couple of Ping Buddys on Ebay a few months back, but haven't seen one anywhere else for sale. Hopefully there'll be another small, unobtrusive "in" product that works as well for those of us with small, limited space cockpits & that doesn't have to be "stuck" somewhere, and isn't wireless-dependent & battery dependent (...something like, maybe, the Ping Buddy!? 
) Mac