This is the first mobile handset released by Nokia that possesses a touchscreen in a "candybar" phone form factor. It is also the first touchscreen handset from Nokia that runs the Series 40 Operating System. Previously released touchscreen devices from Nokia have either not had a physical keyboard, or they have had a slide-out, full-QWERTY keyboard.
There is also hardware upgrade version available of this phone, which can be identified from RM-775 and X3-02.5 codes in the sticker which can be found under the battery. The X3-02.5 (RM-775) differences compared to X3-02 (RM-639) are: 1Ghz CPU vs 680 MHz CPU, 256 MB ROM vs 128 MB ROM and 128 MB RAM vs 64 MB RAM.