How do Adjustable Shocks Work?

[jm1234]

Anyone have a link or care to post a quick overview of how the adjustable shocks in the M3 work? I'm just curious if they are oil shocks or something else entirely? I've read marketing material about a lot of types of shocks (gas, magnetic, etc...) in different cars but I really don't know technically what the hell they are all talking about nor what the M3 has.

Thanks