Rotring Essential Trip Gray Multi-Funtional Pen
The Trio is a single pen with 3 different tips.  The ingenious design of the Trio is the gravity controlled tip selector.  There are 3 tip symbols at the top of the pen (black ballpoint pen, 0.7 mm pencil and PDA stylus.)  Just hold the body of the pen horizontal with the appropriate symbol on top and that's the tip that will come out when you push the top cap down.  Eraser is under the cap.