The best filter in the world can't do its job if there are leaks in the seal of the airbox. That's why Twin Air provides a complete line of products to ensure a leak-proof, fool-proof fit. Twin Air's Power Flow kit comes with a rigid, lightweight, billet aluminium cage that provides a tight seal to the airbox and replaces your flimsy plastic stock cage. Includes a Fire-resistant Twin Air Filter. (POWER FLOW KIT 154222C -INC AIR FILTER FR, ALIMINIUM CAGE) GAS GAS MX MC250F 21-23 MC450F 21-23 GAS GAS ENDURO EC250F 21-23 EC350F 21-23 GAS GAS XC EX250F 21-23 EX350F 21-23 EX450F 21-23 KTM MX 250 SX-F 19-22 350 SX-F 19-22 450 SX-F 19-22 KTM ENDURO 250 EXC-F 19-23 350 EXC-F 19-23 450 EXC-F 19-23 KTM XC 250 XC-F 19-22 350 XC-F 19-22 450 XC-F 19-22 HUSQVARNA MX FC 250 19-22 FC 350 19-22 FC 450 19-22 HUSQVARNA ENDURO FE 250 19-23 FE 350 19-23 FE 450 19-23 HUSQVARNA XC FX 350 19-22 FX 450 19-22