Note: If You enter search term "6303RMX" into eBay or Amazon, you will note The provision of o.e.m size bearings - 10X42X13. "6303RMX" is stamped around the OEM idler #two bearings. I've strong doubts about these becoming high-quality bearings, such as the Koyo bearings labeled as getting created in Japan https://www.aaacollectionagencyinc.com/our_certifications.html