ok so i have a 2006 focus zx4 my stock intake is still on i was lookin at it the other day and noticed a large "box" going to the downtube that then leads to the filter box. what exactly is that large box for? all it looks like is a tube incased in a box. theres a clear "tube" on the side with red marker indicators and on the top says "press to reset" can anyone tell me exactly what this box is? and is it necessary?