What's the oldest computer part/peripheral you still use?

[GhastMaster]

In the spirit of the OP's question, my Beyerdynamic DT150 headphones are the oldest item i purchased at roughly 5 years.

I also have a Bose 321 system that is technically older(early 2000s), however, I added it 3 years ago.

DeeBye. I found alf when I was in 8th grade, nearly 20 years ago. He has been sitting on my desk(usually monitor stand) since i bought my first computer. Picture is not mine.