What bung is this?

[ultimobici]

Any ideas what system this is?

TIA

[quattrings]

looks like the expander by canyon.
There is a similar system made by Deda, for the US folk who have troubles getting hold of Canyon products.

[xena]

I am sure Ritchey made something similar to the photo.

[NiFTY]

That's the acros headset. Headset preload is set underneath the stem, rather than by a conventional top cap and expander.

[latman]

focus have the same system in Australia

[duvivr6]

it indeed looks like the canyon headset, but I am in Germany and have not been able to find one for sale from Canyon...

Anyone have a link to the so mentioned deda one can't find that either

[quattrings]

http://www.wiggle.com/deda-expander-bung/

Not the same sytem when it comes to preloading the headset but I presume most people buy it because of esthetics.

[5 8 5]

quattrings, you've linked to a standard expander? That isn't the same thing as the Acros push-in bung.

[veloflyte]

Actually I had an idea like this a few years ago. I may still produce one...

[drchull]

Can't really see the headset but could be either the acros set where they didn't put the plug (it is really decorative) in the top, or a standard set with the bung removed after, someone gave a link for one of those removable bungs, most that aren't a starnut are removable.
I have one of the acros ones on one of my bikes. Works well, find the top cap rattles sometimes. I believe some forks depend on the bung being there for structural reasons, I am not sure but I think my Scott (Foil) manual said needed to stay in after installation of fork. Could be wrong though.