Review on V623ZZ Miniature V Groove Bearing 3X12X4Mm by Vivek Allen

I bought these for a linear guide along a DIN rail. In total I plan to use four of these to compensate for their small size. Each bearing should support about 12.5 lbs. I will update my review after using them a bit, if they last a while I will upgrade to 5 stars. So far they make a fairly stable and smooth impression. They are very quiet at the low speed I use them for. The actual measured outside diameter of them does not differ by more than 50 microns from what I received. I'm deducting a star (actually it should be half a star) because the packaging they came in was completely covered in oil. Not in your pocket. Outside. never seen before