You're right; I thought it was either cotton, like a K&N air filter, or foam.
My XR650L had a paper air filter as stock equipment, but I quickly replaced it with a foam, Uni air filter. I have Uni and No-Toil, foam air filters for my Honda CRF250X. My Kawasaki KDX220 has a foam air filter, as do both my Zongshen motorcycles. I haven't seen a paper air filter for quite a while.
However, they do a very good job, as long as they don't get wet, with either water, or oil.
__________________
Spud
"Never argue with an idiot. He will drag you down to his level, and beat you with experience."
Mark Twain
2015 Zongshen ZS250GY-3 (RX3)
2006 Zongshen ZS200GY-2 (Sierra 200)
2005 Honda XR650L
2004 Honda CRF250X
1998 Kawasaki KDX220
Mods made to my Zongshen ZS200GY-2:
http://www.chinariders.net/showthread.php?t=6894