Not sure if the balls aren't perfectly round or if it's just metal to metal but after putting them on the underside of the board act as a shelf, we noticed that they sound quite clumsy and loud. They're really cheap and they work, but don't use them when the baby is sleeping or when someone around you is defusing a bomb. I think the more weight they have the more noise they make. Functional, practical, but not quiet.
Enhanced Performance Sydien SCS12UU Bearing Bushing Diameter for Precision Machinery
4 Review
Electric Guitar Strings Ernie Ball 2221 Regular Slinky - (10-46)
5 Review
π§ High-Quality TIMKEN 6203 2RSC3 6203 2RS Bearing - Size: 17X40X12mm
4 Review
π Wheels Manufacturing Ball Retainer Bag: Convenient Storage and Protection for Your Ball Retainers
6 Review