K&N Engineering, Inc. is offering a mail-in consumer rebate in the amount of $25 on qualifying purchases of K&N performance air intake systems. This rebate is limited to purchases made between August 1, 2015 and August 31, 2015 at participating in-store, and online retailers. The K&N air intake system mail-in rebate is valid in all 50 U.S. states, including the District of Columbia, and Canada.