The forward offset, along with the slanted and angled filter are designed specifically to help provide more leg clearance. The 1.8in filter has 160 Sq. inches of filter surface area and the 2.8in filter has 261 Sq. inches of filter surface area. Largest side mounted air box and filter surface area on the market. Max volume air cleaner kit for M8 motors. Oversized external breathers. Internal velocity stack. Made in the USA