Manufactured in the Netherlands using a special dual-layer foam, formulated for maximum filtration and optimum air flow. Coarse open-pore foam catches airborne dirt, grime and sand while the fine open-pore inner foam acts as a second filter to trap the smallest particles. Top quality materials and superior construction allow the filter to be used over and over again without any loss of performance. Made to fit the factory air box and are a direct replacement for original equipment filters. No need to change carburetor jets or settings. Yamaha WR250 F 03-14, WR450 F 03-15