1. Press and hold the button or wrench on the battery cover, pull down the battery cover and twist it slightly. Some headphones have a small raised button on the battery cover. You need to press and hold the button to open the battery cover.
2, the battery cover is tight, you can use keys or other gadgets to help open it. Insert the tool into the gap between the battery cover and the earphone, and then twist it slightly to open the battery cover.
3. The above methods still can't open the battery cover. You can check the instruction manual of the headset or contact after-sales customer service for consultation and help. The full name of English AB-level test is "Practical English Test for Colleges and Universities" or "PRETCO" for short. CET-3.