Don't bother with this pen-based styli. It does not fit properly in the Treo 650, sticking out a bit. The pen is just inserted in the hollow tube top of the styli - no catch to hold it on, just friction. As a result, the stylus would sometimes come out with the pen still inside the Treo. The pen shook out easily, but this was a hassle.The pen is too tiny to be useful anyway. Get a regular replacement styli instead and skip this one. In the end, mine broke after just a few months. Since the stylus did not properly fit the Treo (too tall), after a while the plastic top broke off.