Pro Design Airbox Filter Kits for the Kawasaki KFX400 replaces the faulty stock and restrictive air filter and adaptor to give you the performance you want. Your filter can now remain in place without the restriction inherent with the stock mounting lid. Includes a positive O-Ring seal, 2 Stage High Volume Foam Air Filter, with a third stage filter wrap, and all mounting hardware. This kit can save hundreds of dollars of machine repairs. With the Pro Flow Kits, in dry riding conditions you can completely remove your airbox lid and maximize your air intake.