Product Description: Contour Master Header Drive Shaft. 1-3/8" 21 Spline Slide Collar x 1-18" Hex Clamp. C-to-Cmeasurement: 24" ( 610 mm). NOTE: It may be necessary to cut this driveline to length: Verify thelength by ensuring that sufficient overlap of the drive tubes exists in all working positionswithout the possibility of bottoming out. It may be necessary to cut this driveline to length. Verify the length by ensuring that sufficientoverlap of the drive tubes exists in all working positions without the possibility of bottoming out.