everything is ok !!!
The internal diameter of the 2 Linear Motion Ball SC8UU they have sent is 10 or 12 millimeters, that is, for 10 or 12 mm rods. I have rods of 8 millimeters which is for those who ordered those bearings and you can see in the picture that they are very loose and do not serve me. I need a reasonable solution, but I will open a dispute. Thank you