Oliver/White Series KM 440 Seat & Air SuspensionOne New Aftermarket Oliver White Series KM 440 Seat & Air Suspension Oliver and White Series Tractors with Original Bostrom Suspension and the Weight Adjustment Knob Behind the Backrest OR the Weight Adjustment Knob on the Left Side of the Original Seat & Suspension: Oliver Tractors: 77, 88, 500, 550, 600, 700, 770, 990, 1250, 1250 A, 1255, 1265, 1270, 1355, 1365, 1370, 1450, 1465, 1470, 1550, 1555, 1600, 1650, 1655, 1750, 1755, 1800, 1850, 1855,