BBR's exclusive U-Flow Air Filter System turns the filter around so it faces backwards, keeping it shielded from dirt and mud. It comes with a high-volume oversized Uni Air Filter maximizing air flow. This innovative upgrade allows the bike to be jetted for optimum performance. The U-Flow delivers a high volume of air to your carburetor resulting in sharper throttle response. Does not fit stock carb. Works with TTR110 BBR 24mm Carb Kit.