Benz has 3 types of cabin filter.

1) A Dust Filter
2) A Combination Filter (dust filter with a bit of carbon filter capabilities and finer filter material.
3) A Active Charcol Filter (fitted with a dust filter also in W211)

The active filter was an option on earlier cars and on the low end of current models.

If you don't have a button for it on ths A/C control panel then you don't have it, just use a combination filter.

__________________
Alex.

MB Tech
Sydney, Australia
Volvo 122S
W201 190D 2.5 manual
W202 C240
W203 C32