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 movement of air 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.1983-1987 fits HON XL600R