Mercedes Alpine AL2910 or AL2199 Radio Codes
It is quite simple to remove your Alpine radio. You will need a set of radio release keys. These are inexpensive and are around £3 - £5, you can obtain them from a local car audio shop or Halfords.
Once you have the radio release keys, push them into the 2 holes in each bottom corner of the radio (See image), apply a little pressure and the radio will release from the dashboard. The radios label will be located on the radio's casing.