Uni Filter 87-91 KTM 125/350 2 Stroke / 82-96 KTM 500 / 540 / 550 2 Stroke / 85-89 250 Air FilterUni Filter Dirt Bike Foam Air Filters have been unsurpassed in both engine protection and overall performance for over 50 years. Their unique two stage design produces more horsepower and more torque than any other air filter. This Part Fits: Year Make Model Submodel 1991 KTM 125 EXC Base 1987 1991 KTM 125 MX Base 1985 1989 KTM 250 MX Base 1985 1988 KTM 250 MXC Base 1989 KTM 350 MX Base 1985 1988 KTM 350 MXC Base 1985 1993 KTM 500 MX Base