Air bonnets play a vital part in blow through systems. They can make or break your whole combo. The CSU air bonnet was specifically designed for blow through use. This is one of the best bonnets on the market. It's a simple and straight forward design that flat out works.  It has been proven to work on everything from daily drivers to 1600+hp race cars. Dyno and track proven to lower intake temps and make more power over other designs. Our bonnet work so good that other competitors have copied our design and claim proprietary design of their own. Don't be fooled by these PERFORMANCE IMITATORS who's own R&D program stands for nothing more than Rob & Duplicate. Our bonnets have a height of 4" and an inlet o.d. of 3 1/2".