I am a true believer in Twin Air filters. I bought one of these in 2007 for my 2006 Honda TRX450R. Every time I ride for a weekend I use the biodegradable cleaner and recharger to re-install the filter. I ride with 4 other 450R's who have UNI and K&N filters. I bought the cage for the twin air filter which is well worth the money. We all run an open air box and I have compared the soot on the inside of the intake after removing the filter. Mine is consistently the cleanest. We ride through a lot of mud, dust and water and I have never had a failure due to the air filter. If that wasn't enough, the 450R has constant maintenance requirements with the valves. Knock on wood but mine is the only one that hasn't had to have the valves, springs and seals replaced yet. I believe it is directly related to my air filter. Everyone does the maintenance and cleans the filters religiously but I am still running original valves. I have also noticed that when I adjust my valves they are not nearly as tight as the rest. Twin air and No Toil in my opinion have come up with the best design for power, cleanliness and reliability than anyone else in the industry. I feel confident riding in any condition that my twin air system will protect my intake. Highly recommend. Well worth the price you pay.