This wooden strip is the guide rail for the inclined feeder chain on a combine harvester. It sits along the floor of the feeder housing, providing a wear surface that the chain slats ride against as they carry crop material from the header into the threshing drum. Over time, the wood surface wears down from continuous chain contact, which increases chain slack and can cause the slats to strike the housing floor. Replacing the strip restores the proper chain-to-housing clearance and prevents metal-on-metal contact that accelerates chain and housing wear.