it's basically just a fan that turns on when you accelerate. You hook up a switch that makes contact when you start accelerating and puts more air to the intake. Do they work.. well, look at their claims. "UP to 15 more hp" for the single kit. Not worth the money. My buddy had one of the old ones and it was noticable on the dyno for about 8 or 9 more horsepower on his integra. You can put a few in a row also, to increase it, but still, you are talking about a good bit of money for a little gain. The ones they used to sell on ebay had plastic fins, and the worry was what would happen if it broke and a plastic fin went into the motor. This looks like it might be all metal, and if constructed well it might be alright, but it is still a waste of money in my opinion.