The model code of rolling bearing is used to indicate the inner diameter, diameter series, width series and type of bearing, which is generally five digits. Codes are divided into basic codes, post codes and pre codes.

The terminology of bearing 57308 is explained as follows:

1 and "5" indicate the bearing type number, which is a thrust ball bearing;

2. "73" means that the bearing can bear the axial load of 73;

3. "08" indicates the bearing inner diameter code, and the bearing inner diameter 8 times 5 is equal to 40mm.