Features: Twin Air dual-stage filters are the choice of top factory teams and riders worldwide . Dual-bonded foam design filters out even the smallest dirt particles, while allowing more airflow than two separate layer filters (flow bench proven) . Flat foam sealing ring provides a secure seat against the airbox, even in the worst riding conditions . Twin Air filters are slightly smaller than stock, making them easier to change while increasing dead air space around the filter for better performance . Backfire filters include a laminated layer of backfire-retardant foam . Air filter cages available separately for some models.