 There are two types of Sonnet rechargeable battery, the standard battery and the smaller micro battery. Both types are attached to the audio processor in the same way. Plug in the charger to either a wall socket or your computer. The white indicator light shows that the charger is working correctly. The battery has a lip on one of the narrow sides and a ridge on the other narrow side. To insert the battery into the charger, hold the battery at a slight angle and insert the lip under the transparent side of the charging slot. Then tip the battery towards the white side of the charging slot until the ridge snaps into place. Do not press hard. If the battery is lined up correctly, it should fit easily into the charging slot. The blue indicator light shows that the battery is charging. When the indicator light turns off, the battery is fully charged. This takes up to four hours. Gently remove the charged battery from the charger. Insert the hook on the control unit into the matching groove on the rechargeable battery adapter and push down until the release lever engages. Hold the battery at a slight angle with the lip of the battery touching the ear hook side of the adapter. Push down gently until the ridge of the battery snaps into place. Then replace the battery pack cover, ensuring it is in the unlocked vertical position. If you are using the micro battery, the smaller micro battery pack cover supplied in the kit should be used. For additional security, lock the battery pack cover into place using the plastic screwdriver.