Gewa Cello Mirror 20cm

This is excellent for guitars. I don't own a cello, so don't know if it shows the entire inside. Seeing is one thing, but working on it... if you have the right tools!
It does all I expected and hoped for and instantly shows me the wiring inside and whether the cable is screened or not... and do I want to remove a pot and re-solder with better cable.
It is stated as a 20mm dia. mirror, but is marked for some reason as "10" - can't explain this.
Just noticed that it has the word "Stainless" etched on the handle, so not sure if some previous stock was chrome ? Not a problem either way.