They are basically a very good copy of the oem ones - I've used them in the past you get a good couple of years out them before they start to go stale but I've seen the oem ones go white wormy on my fiancee's 1 series after 2 years
http://pages.ebay.com/link/?nav=item.view&alt=web&id=191584714688&globalID=EBAY-GB
They are the ones I have