 To attach Roger 21 to Sonnet, first remove the standard battery pack cover. Make sure that the battery pack cover lock is in the vertical unlocked position. If it is in the horizontal locked position, unlock it with the plastic screwdriver. Then pull back and completely remove the battery pack cover. Slide the Roger 21 battery pack cover over the battery. Use the plastic screwdriver to turn the lock into the horizontal locked position. The Roger 21 can be paired with a range of Roger microphones in different situations. For more information, please consult the user manual for the specific microphone.