The clear plastic? It doesn't have a part number in the parts catalog. If you check your old cover and find a part number you can use that to buy a new one from dealer, worldimpex, 1stvwparts. Here is how to read the part number: http://www.myturbodiesel.com/1000q/VW-Audi-part-numbers-system-explained.htm
If there is no part number it's not a separate part and you would have to get one used.
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