has anybody tried these? they're the best i pulled my first one off after one ride and it was covered in crap. i cant imagine all that being on my air filter. they are also relativly cheap under $20 for three that are reusable. you just clean and oil them the same way you do a airfilter. the advertisements say they block 90% of dirt and allow 95% of airflow to still pass through. totaly worth the money!