The All-New Patented Banks Ram-Air Differential Cover WIPES OUT THE COMPETITION! When it comes to product development, we only make products that increase performance and beat the competition. So when we tested the popular Diff Covers on the market, we were shocked to find out that they actually hurt performance. This lead to the development of something so New and Incredible that our performance design has a United States Patent. Look, when we set out to build a product for your vehicle, we only engineer the best. What else would you expect from a company with a winning legacy that spans decades.