ipccam 10 Pack 6001ZZ Deep Groove Ball Bearing, Precision Bearings 12mm X 28mm X 8mm, Double Shielded Metal Seal, Suitable for Linear Motion, Wheels, Skateboard, High Speed & Durable

These are some extremely low quality bearings. I purchased a package of 10, several of them had bent spacer rings, and were practically seizing up. None of them spin very well at all. It's also false advertising. These bearings have 7 ball bearings that are widely spaced, the photo shows 9. This is definitely "you get what you pay for". Do not expect to get quality precision bearings if you buy this.

Was not true 12mm id was 11.49 had to turn down bolt to make work