Twin Air high quality air filter and fireproof, made with 3 different types of foam density, achieving greater air intake and maximum retention of dust and dirt. The best performance and maximum protection for your motorcycle engine. For the PowerFlow Kit for KTM 525 EXC-F (2000-2006), 250 SX-F (2006), 450 SX-F (2003-2006), 250 EXC-F (2006), 450 EXC (2003-2006), 505 EXC-F (2000-2006).