Air filter replacement

[pleasestartnow]

Hey everyone, I am thinking about changing my air filter in the van, 1.6 diesel. You can see the the existing one in the picture below, and I have gone through the forums but can't seem to find anyone else mentioning one similar to this. What would I replace that big drop part with, any ideas? There is no issues with it (as far as I know) but I have never changed the air filter since I got the van a few years back so I think it is past time it gets done. What is the rubber hose attaching to the circular box on the engine? the setup of it doesn't make a huge amount of sense to me, if that big drum is the filter there is no outgoing piping from it so to me the air would just go in there and stay there? But I am thick so maybe someone with more sense can point me in a replacement/upgrade option.

[lefty67]

The air filter is inside the big round drum. Take drum out, take top off and filter is held in place by a nut on a bar.

[pleasestartnow]

Sound cheers for that. Will get on it this weekend.