Part no 15-3909.FR (oro2u.com)
Twin air flame retardent BACKFIRE filter for powerflow kit
HONDA TRX450R 2004 - 2005,
KAWASAKI KFX400 2003 - 2006,
SUZUKI LTZ400 /LT400 Eiger 2003 - 2014,

Twin Air Foam Air Filter - 15309FR
Twin-Air dual-stage filters are used by factory race teams and leading riders around the world Dual-bonded foam design removes even microscopic dirt particles, yet allows more air flow than regular two separate layer filters (flow bench tested) Flat foam sealing ring maintains a secure seal to the

airbox, even in the worst riding conditions Twin Air filters run slightly smaller than stock, making them easier to change and increasing the dead air space around the filter for better performance.