I want to thank you all for the info. I read through the manual, rented a tank so I could link it to my wireless and get to play with it. I've had a couple of dives with it so far, and I'm very happy with it. Even though it's similar to the i550, the i770 is quite a bit different. For now, I'm still packing my i550 in my reg bag any time I go diving, just as a fail safe. We'll see if I have the weight to spare on my up coming dive vacation though. I've had it loose connection a couple of times, but being 6'-4" I have easily reach my arms out over 3 feet away from the transmitter. Any time I have lost link, simply pulling my arm back has linked it back in a matter of seconds. Haven't worked with Nitrox yet, as I've jut gotten my cert, but I'll be diving on it during my trip, so I'll work on getting that setting switched over. Again, thanks again for all the pointers and tips everyone.