2022 Transition Sentinel Carbon GX Headset Bearing Kit Chromag 2RS is the most common

2RS is the most common terminology for this type of seal and it literally stands for 2 rubber seals

These are better than other generic bearings you may find

No need for a cable and a lever on handlebarsAffordable hydraulic cartridge height adjustable postAluminum construction with adjustable air preload1-bolt micro-adjustable seat rail clamp

Also known as ACB518K

Angle / Chamfer (Deg): 45 / 45

2022 Transition Sentinel Carbon GX Headset Bearing Kit Chromag 2RS is the most commonComplete replacement headset bearings for this bicycle. 1 x "official FSA" upper bearing 1 x "Rad Bearing" lower bearing correct for the bicycle headset