Wish I lived next to RiffRaff to eliminate shipping but still the best price on these filters. $15 less than autozone and better filter quality. Riffraff's filter has metal mesh on the inside which protects against filters falling apart and getting sucked into your turbo !

Great Filter and fit perfectly on the UpGr8 4" Aluminum tube. Heavier Duty than other 6637 filters out there. Another great product by RiffRaff.

Love it! Love the price!

Excellent product , a must have for any 2001 7.3 .Very competitive pricing including postage to Australia. Thanks RIFFRAFF!

This is a better quality filter at a cheaper price than the 6637 replacement filter I bought at NAPA.

Great product and mod. Fit right on my K&N cold air intake.

Every time I place an order from Riffraff I always add 1 or 2 of these just to have a spare around. They work great i have been using them for years! Great Price and fast shipping. Dont get much better! Thanks RiffRaff Diesel

The conversion to this filter for my f250 was very simply. I have had it for 250 miles I can see more boost than a clean K and N filter

like others say you can get the pre filter and the 6637 filter for cheaper than your local auto parts store. definitely suggest the pre filter, it is very well made.