Its an induction kit as said but the theory behind the design is that the air enters into the larger carbon fibre chamber and slows down a little, but as soon as it gets "sucked" into the normal witdth piping it gains momentum and as a result acts as a slight ram.. so the air velocity accelerates and "forces" into the engine.. as a result more air = more power.. Top Fuel also made what is dubbed as the "whale penis" for the Civics, for me that seemed a better design as it started as quite big at the filter end and then funneled down to the normal intake size.. as a result as the air is sucked