What are the differences between DT 231 Pro and Trendline DT 231?

[awiegote]

The only differences I could find on Beyerdynamics webpage was a lack of data for ambient pressure for one of them. I would guess the Trendline is inferior, since they're selling for substantially less - but maybe the extra price is just so you can be a

Pro?

P.S. Don't try and tempt me to get better headphones... I will not come to the darkside!