Sealed chromium steel bearing with black oxide treatment on the outer surfaces of the bearing races.
This item contains both upper and lower bearing.
-AB-2050 is the upper headset bearing for Trek Speed Concept frames and has dimensions 14.2x25x6.5mm, 45x45 deg
-AB-2052 is the lower headset bearing for Trek Speed Concept frames and has dimensions 27.1x38x6.5mm 36x45 deg
