It's a 9 or 10 litre plastic storage box with a transparent lid. In here I place my naphtha for rinsing and my parts containers. I've got two ports for my hands to enter, so I can clean & manipulate the various different parts. The fan blows out the back, drawing air in through the hand holes.
At the back I've got a standard 120mm computer case fan. These electronics are by no means complicated, and do the job of fume extraction quite well.
Depending on where I'm working, I'll either use this near a window or with an additional ducting tube which gets those nasty hydrocarbons away from me.