Compatible crown races for Ritchey headsets. - This adaptor allows 36 headset bearings, such as those from Chris King, to fit the Ritchey WCS Carbon Adventure fork that feature a 45 crown race - This adaptor is designed for the Ritchey Carbon Adventure fork, but it will work with all Ritchey carbon fiber forks, though with possible slight cosmetic inconsistencies - Stainless steel - Use of this adapter will effectively increase fork length by 4.4mm