One-piece aluminum backing plate features patented hidden breather technology. Each hidden breather is o-ringed at the heads and exits at the mouth of the injector/ crab to provide efficient engine breathing, eliminating the need for any external hoses or hardware. Radius air inlet provides maximum performance by providing unobstructed airflow. Backing plates are available in Standard, black powder coat, or chrome finish. Kits are available with standard red or synthetic black filter elements. Synthetic filters feature a black synthetic material that is water resistant and never needs to be oiled; just wash and re-use. All kits include high-performance filter, backing plate and steel outer cover. All necessary hardware and instructions are included with each kit. NOTE: Kits with Synthetic filter are exempt per c. a. r. b. ref. e. o. # D-639-4, Exhibit a.