This autocontour skid mounts to the underside of the grain header to sense ground contour and signal the header height control system. It slides along the field surface ahead of the cutterbar; the pivot arm transfers vertical movement to the control linkage. A worn skid reduces ground-following accuracy, causing the cutterbar to scalp or leave stubble uneven. The replacement part is formed to the same profile and hole spacing as the original assembly so the linkage geometry is preserved. On installation, verify the chain length matches the original and that the skid pivots freely on its mounting bolts.