Machter EGR Block Off Plate for Duramax Diesel 2004.5-2005 LLY Blocker Stainless Steel This plate eliminates the recirculation of exhaust gas into the intake. Keeps soot out of the intake manifold and may improve engine performance! This plate is simple to install and can be removed at any time. 15-20 minute installation time! High quality STAINLESS STEEL part made on a CNC laser.