Beairng Service, Inc.'s Product categories are assigned internally by Bearing Service. They are used to classify parts into types based on similar properties. They are typically not used for pricing. Custom pricing is done with Product Price Types. See more about this distinction at Pricing Philosphy and Product Classification.
Product categoires are useufl in determining quickjly what other vendors might manufacture similar products. For inforamation related to this see the Vendor Product Matrix.