Recently I purchased 4 bearings for a cincinnati arrow ballscrew support. Each pair were purchase in EBAY from different vendors and the 4 bearings are counterfeit. DON'T BUY PRESICION BEARINGS ON EBAY.
I realized the bearings are counterfeit because the QR CODE in each box only give you the code model and if you download the application from NSK or WBA they will tell you if they are counterfeit / original and it will give you a web page with the real measuring values for each specific bearing.
Also I measured the high of the bearings and didn't correspond to the values on the box.
Be careful and don't waste money on Ebay.