Paint paperless, practice math, leave messages. Captions are possible with the enclosed pen or fingernails. The surface of the display is pressure sensitive, i.e. the tighter you press, the thicker the stroke. Press the clear key again to get a blank display. On the back there is a locking switch to temporarily secure images. Supplied incl.1 button cell 3V CR2025, color: blue, size approx.: 25.3 x 16.0 x 0.85 cm.