Etymotic MP•9-15 Music•PRO® Electronic - Manual (Page 5)

Battery Insertion
5
The battery must be inserted
correctly or the device will not work.
1. The battery compartment
is located on the underside
of the device.
2. Open the battery door.
3. Remove the yellow tab
from the battery.
4. Insert the battery
with the flat side facing up.
5. Do not force the battery.
into the door.
Battery
Compartment
#10 Battery
Inserted
Battery
Door
Note: The door will not close
if the battery is not inserted correctly.