This left arm is part of the subsoiler assembly on the header of a grain harvester. It connects the linkage to the depth-control mechanism, translating vertical motion from the hydraulic cylinder into the raising and lowering of the tine bank. A worn or bent arm causes uneven depth across the header width, leading to inconsistent soil penetration and increased draft load. This component is machined to match the original pivot-bore geometry, ensuring the linkage maintains its designed travel arc without binding.