Thanks daRe, these things really are beneficial. They have a fan that is nothing more than a large PC case fan, but it constantly circulates air through a filter to keep out dust and regulate moisture. Keep the filter cleaned, which is washable, and it will be just as clean when you take it out as when you put it in. It is made of very thick mil material so if your thinking it won't last, think again. I was reading reviews when I bought this one and many ppl were using them in a corner of their garage with shovels and other various things thrown up against them and of course nothing gets close to the bike because its surrounded by air. It prevents someone from accidentally dropping or knocking something into the bike too. Its more or less added assurance that the bike doesn't get those magically appearing chips, nicks, etc when its just sitting during non-riding weather. They sell for 339.99 right now through Amazon.