You’d be amazed at the dirt and debris that can end up in your fuel carrier and then into your fuel tank. Twin Air’s monofilament screen pocket inserts into your fuel tank and catches the particles as small as 40 microns (.00165”) while allowing the gas to flow freely. The flange is custom-sized for each modern 4-stroke model to ensure a leak-proof seal. Just remove the filter periodically, turn inside out, and clean the debris that could have been in your engine. Twin Air Fuel Filter to fit with threaded cap. GAS GAS MC250F 21-23 MC350F 22-23 MC450F 21-23 KTM 250 SX-F 13-22 350 SX-F 13-22 450 SX-F 16-22 HUSQVARNA FC 250 14-22 FC 350 14-22 FC 450 14 22