Lis listing includes both the upper and lower headset bearings, two bearings included in sale.

For bikes using the Giant OD2 (Overdrive 2) Road headset, all model years

OD2 Mountain bike is a different headset and takes different upper bearing from this kit.

Upper Bearing - ACB418H6 (MR136)

Lower Bearing -  ACB45451375 (MR137)

High quality anti rust black oxide lower bearing. Both upper and lower are precision milled cups and packed with high grade grease.