This chain tensioner maintains the correct tension on the drive chain that connects the metering mechanism to the seed drill's distribution system. It is mounted on the pivot arm of the chain drive, where a spring-loaded arm applies constant pressure to the chain to prevent slack that would cause skipping or uneven seed metering. A worn or seized tensioner allows the chain to run loose, leading to irregular seed drop rates and potential chain derailment. As an original component from the implement manufacturer, the tensioner's spring rate and arm geometry match the original assembly's load requirements, so no adjustment shims or modified mounting brackets are needed. On reinstallation, ensure the pivot bolt turns freely and the spring is seated in its locating pocket.