39mm Air Filter for 125 cc 150cc 200 cc ATVs Quad 4 Wheeler Pit Dirt Bikes 125cc Go Karts Dune Buggys 39mm Air Filter. Top Quality Guaranteed. It fits most Chinese for 125cc 150cc 200cc ATVs & Dirt Bikes and 125cc Go Karts, such as Taotao/Coolster ATVs and Enduro/Oil cooled/SSR/Coolster Dirt Bikes ; Inside diameter: 39mm Higher air flow than normal filter for maximum power ; Race tested for performance and reliability ; Race filters increase air flow by up to 25% over standard filters ; High quality ensured