This set of five left-side blades is part of the straw chopper assembly on a harvesting machine. The blades are mounted on the chopper rotor and interact with stationary counter-knives to shred the straw stream discharged from the threshing unit. A dull or missing blade reduces shredding quality, leaving long straw strands that can interfere with subsequent tillage or baling. The set includes the mounting screws; when replacing, use new hardware and torque each blade to the specified value to maintain rotor balance.