A simple keychain featuring the yin-yang symbol and the bagua (the trigrams). The bagua are in the
Fuxi configuration (the original version), not the King Wen configuration (the one often used in Feng Shui).
The chain itself isn't included and will need to be purchased separately. I found mine at
keyring.com, specifically
here and
here. (I shortened the first one to get the length I wanted.)
Pendant version here
Other options:
King Wen configuration
Fuxi on one side, King Wen on the other
No bagua