Here's what I found after I did some searching:
"Part Number is 015-997-94-48 and you can order from Fastlane and the usual suspects." -- I checked, they are $.34ea from Phil.
Also some useful info that I did not know in this thread
Has everyone checked their oil filter o-rings?
Hope this helps!! I remember when I got my 240D, I ordered 20 of these made of vitron.