This 6004-2RS ball bearing is a high-precision premium quality sealed deep groove 20x42x12 ball bearing made to ABEC 3 precision standards from AXIS. What sets this 6004-2RS bearing apart from others is the ABEC 3 precision standard that this bearing is made to, the grade 10-balls used, and the superb electric motor quality rating (EMQ). ABEC 3 means that the bearing itself has a micron deviation from a nominal of 20.000mm of -8 micrometers.