Contour Master Header Drive Shaft. 1-3/8" - 21 Spline Slide Collar x 1-18" Hex Clamp. C-to-C measurement: 24" ( 610 mm). NOTE: It may be necessary to cut this driveline to length: Verify the length by ensuring that sufficient overlap of the drive tubes exists in all working positions without the possibility of bottoming out. Fits Cutting Platform models: 90 Series, 918, 920, 925D, 930D, 936D, 900 Series; Corn Head: 90 Series.