The Deda HSS Carbon Spacer set is a three piece set with spacers of 3, 5 and 10mm. These headset stack spacers work with the Deda HSS Headset to properly customize your cockpit to get the perfect fit. This can increase the front end stiffness of your bike or improve handling depending on your specific setup. The Deda HSS Carbon Spacers are a quick way to further customize your favorite bike.