Edit By DR:
These are stainless steel filters that are able to be cleaned and last a lifetime.
They are a US product but don't seem to be imported to UK - although some US vendors will ship them here.
With the news that Aprilia are changing the filter design, this may be a good idea.
Scottsperformance
Problem with them is that even though they cost reasonable $79, shipping is $60 (the same shipping price for 2 though). Take into account customs possibility tho.