I found these tidy little UNI oil/foam air filters by accident. One of my K&N style air filters fell off about a thousand miles from home and a large version of the UNi was the best I could come up with. When I got home I did some searching and found these pod type filters that fit perfectly. Having read tests on K&N filters that show they keep out the big stuff but do little to prevent dust from entering the motor, in the past I have used K&Ns only because they are better than no air filter. Most industrial air cooled engines that are subject to dust are equipped with cleanable oil soaked foam of some sort, same idea as these UNIs. UNI sells aerosol foam oil specially made for soaking the foam. I'm confident that this type of filter will do a good job of keeping grit out of the engine, but was concerned that air flow might not be good enough for full power. Tested on Dyno hill, the UNI s gave the same reading as the K&Ns which give the same reading as no filter, that is hit the base of the hill at 70 mph in top gear (10%grade) and go over the top at 72 mph , left in top gear. r