My AKG headphones, bought from Digitec in 2018, are labelled AKG Pro K812 on the invoice and cost CHF 770 at the time. I don't understand why they should be so much more expensive now. Apart from the price, these are really great headphones.

Unfortunately, I don't know. However, I can say that I am very satisfied with this KH.

There is only one AKG 812, once you find it as Pro and once without Pro. It's one and the same. Just search for it on the Internet.