These spreader blades are the rotating components that meter and distribute granular fertilizer from the hopper onto the field. They are mounted on the spinner disc assembly, where their shape and angle determine the spread pattern and working width. As the disc rotates, the blades accelerate the fertilizer particles outward, controlling the uniformity of application. Worn or damaged blades cause uneven distribution, resulting in streaking or over-application in specific areas. The original manufacturer's geometry is matched to the disc and housing to maintain the intended throw distance and pattern.