Observe: Should you enter key word "6303RMX" into eBay or Amazon, you will see the availability of o.e.m dimension bearings - 10X42X13. "6303RMX" is stamped around the OEM idler #two bearings. I've strong doubts about these becoming high quality bearings, including the Koyo bearings labeled as remaining designed in Japan https://directoryarmy.com/listings13191136/everything-about-debt-collection-service-in-anaheim