This Airfilter Cage does not have the backfire screen in it. The backfire screen reduces the amouint of airflow causing lower horsepower. By replacing the stock air filter cage on your 4-Stroke KTM with this High Flow cage you will greatly increase the amount of airflow into the engine. Be sure to use a Flame Resistant type of Airfilter with this to prevent any backfire issues. We stock and recommend the NO-TOIL Flame resistant filters to use with this item. Fits the following 4-STROKE MODELS: 2011 250, 350 & 450 SXF models and all 2012 4 models from 250, 350, 450, 500 (SX-F, XC-F, EXC) ALSO FITS 2012 450 SXF "FACTORY EDITION" RYAN DUNGEY REPLICA MODEL