Air filter off of the IRC Vulcan 1/16 scale buggy. It's much shorter than the Xray one. It's very fast, had it clocked at 31MPH running on a oval track. Already used up the front tires to almost nothing. It tends to push a little because of the hard front and soft rear foam tires running the road course, but then again, it's totally stock. My friends getting his going soon, I'll try and get video clip of them together.