Upon many requests we introduce the Cyclone "S" Series Cold Air Intake System (cyclone air filters)  will allow your engine to take in more air on each intake stroke. Made of high-quality materials, the Cyclone Air Filter will stop dirt particles that can harm your engine while increasing its horsepower. The filter features a straight silicone adapter which easily mounts to any 12mm or larger carburetor (all .21-.32, TRX 2.5, and OS .18 engines on any chassis). Filter adapter length can be customized to any length (Stock length is 4") Upon many requests we introduce the Cyclone "S" Series Cold Air Intake System will allow your engine to take in more air on each intake stroke. Made of high-quality materials, the Cyclone Air Filter will stop dirt particles that can harm your engine while increasing its horsepower. The filter features a straight silicone adapter which easily mounts to any 12mm or larger carburetor (all .21-.32, TRX 2.5, and OS .18 engines on any chassis). Filter adapter length can be customized to any length (Stock length is 4")