One of the photos literally shows an actual 1st-gen iPod on top of it.
Edit: OK so maybe the reference of a gen 1 ipod is actually quite useful to me. But it's a 20 year old reference to use. Surely there are plenty of things around that are more useful as a reference point if you need one (or just provide measurements).
Let me Google that for you: https://images.app.goo.gl/hW7G3NaixUd4sNUc7