Wolf Tooth Upper Headset - Blue - IS41-28.6 - 25mm Stack YGroup_7421784981549 With a 50-50 Merino polypropylene

With a 50-50 Merino polypropylene blend

The main differences between the XX1 and the X01 are:

Air Volume per Stroke: 318 cc

02 kg = 20 grams)

dirt and grime will cower and run when they see you coming

Wolf Tooth Upper Headset - Blue - IS41-28.6 - 25mm Stack YGroup_7421784981549 With a 50-50 Merino polypropyleneWolf Tooth Upper Headsets are machined in the USA out of aircraft grade aluminium with superior sealing for protection against the elements. Available in a variety of colours to add some style to your bike. The ZS headsets are for frames with internal bearing cups that are pressed into the frame. The EC headsets are for frames with external bearing cups. In other words, the bearing sits outside of the frame with these headsets. These IS headsets are