This is a seed drill metering component that controls the flow of seed from the hopper to the distribution head. It mounts directly on the metering unit housing and regulates the opening through which seed passes. A worn or incorrectly set metering plate causes uneven seed flow, leading to gaps or overplanting in the seedbed. The original manufacturer’s geometry matches the housing bore and the rotor clearance, ensuring consistent seed metering across the full width of the drill.