Tube Kewler by track fresh. This awesome lightweight system that has a cooling cartridge and a carbon filter. Carbon fiber. 4" inlet 1 1/4 helmet hose outlet. Takes air in filters carbon monoxide out then it sends it thru a aluminum cooling cartridge. All you need to do is cool the cartridge in a freezer or ice before the race! Lasts hours. Hookup a 4" fan and your good to go!