PDA, Ameritrade, only 2 problems so far 1 is if you are using it constantly the device will shut itself down after about 4 hours of use to recharge it's transmitter. Takes about one and a half hours. Other is it dosn't work to good while it's in motion, I don't mean walking around, I mean if you are in a moving car. Sometimes it will "connect", most times it won't. Hell, Ive made money sitting in McDonald's drive thru! The screen is getting a little scratched from the stylus.