Sony MDR-IF33K Teardown
These are some common tools used to work on this device. You might not need every tool for every procedure.
At that time, there was no such thing as an iPod and so the smallest personal audio players were cassette tape Walkmans or compact disc Discmans. With this wireless earph, you could lis, free to wander around the room without or without a relatively bulky audio player attached to your belt.