This size bearing is also known in the bike industry by these part numbers:
27287-1046-004
HSS0130K
TH-873E
MR-122
ACB 3645 SS | Stainless Steel 440C Angular Contact
In standard radial bearings, only three or four of the balls make contact during load. But Enduro angular contact bearings work differently. When properly installed and adjusted (black seal facing in), Enduro angular contact bearings engage all of the bearing's balls to spread the force over a larger surface area, decreasing friction, minimizing wear and increasing bearing life.