RockShox C1 Seal Head Upgrade Kit - DebonAir 35mm Inc Foot Nut - 00.4020.573.000RockShox C1 Seal Head Upgrade Kit DebonAir 35mm The DebonAir seal head upgrade is one of the best upgrades you can make to your 35mm Rock Shox fork. Better small bump compliance and a smoother air spring feel mean more control, less arm pump and more speed! Riders who have compatible DebonAir air springs who dont wish to change travel or need the full assembly can benefit from this simpler upgrade option. Easy to fit! Fits: LYRIK RC C2, RCT3 C1(2019