I accidentally let the battery on my T-Mobile MDA drain beyond recovery so that my MDA wouldn't even turn on or charge. I spent $15 on a universal battery charger that didn't work, then saw how cheap these replacement batteries are. The best part is that they arrive with a partial charge so my MDA was able to turn on immediately and charge fully. Can't speak yet to their ability to hold a charge, but they're so cheap I can't imagine complaining!