Original Cannondale headset spacers for 1.56" steer tubes which is the Headshok size. Set of two 5mm tall spacers combines for a stack height of 10mm. This is an ideal height for use with a Reverse S-Trail stem which has a lower clamp stack height than Cannondale's original stems. Outer Diameter: ~45mm Inner Diameter: 39.88mm Stack Height (Each): 5mm.
