[Efficient]: Numerically calibrated for tuning memory, adjust air fuel mixture with this screw easily; Precise adjustment reduces emissions and helps to reduce off idle spit [O-ring Design]: Air fuel mixture screw adopts an o-ring design to resist engine vibration and increase accuracy and longevity; Comes with spring, washer and O-ring, it is easy to install and replace [Fine Maching]: Precision CNC machined metal screw, beautiful and lightweight; Smooth and bright color, unique appearance; Professional manufacturing process fully meets the standard requirements, stable performance, safe and reliable [Premium Quality Aluminum Material]: This carburetor fuel air mixture screw is made of premium metal material, sturdy, not easy to aging and abrasion resistant, to ensure maximum strength and durability Fitment: for Honda CRF150R 2007-2009, 2012-2016 for Honda CRF150R Expert 2007-2009, 2012, 2015-2016 for Honda CRF250R 2004-2009 for Honda CRF250X 2004-2009, 2012-2013, 2015 for Honda CRF450R 2002-2008 for Honda CRF450X 2005-2009, 2012-2015 for Honda 450R 2006-2009, 2012-2013 for Honda 450R (Electric Start) 2009, 2014 for Kawasaki KLX450R 2008-2009 for Kawasaki KX250F 2004-2010 for Kawasaki KX450F 2006-2009 for Yamaha WR250F 2001-2009, 2011-2013 for Yamaha WR426F 2001-2002 for Yamaha WR450F 2003-2009, 2011 for Yamaha YFZ450 2004-2009, 2013 for Yamaha YZ250F 2001-2013 for Yamaha YZ426F 2000-2002 Colour:black/red Material:metal Package Contents: 1 x Mixture Screw Adjustment Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.