I work in the motorcycle industry and have found the HiFlo filters to be a great filter for the money. They are manufactured by Bike Alert who also makes Vee Rubber, JT Sprockets, and also manufacturers the entire powersport line of oil filters for K&N. Sadly they don't release much if any info on their filter construction and beta ratios, but after tearing down many of their filters and gotten more pertinent info from K&N, I highly recommend them. Standard filters are cellulose based with metal end-caps, leaf spring, and nitrile ADV. Their Racing line includes the K&N 17 mm wrench off nut in addition to safety wiring, synthetic filter media, with the rest of the filter construction the same as their entry level models.