Review on VOLV Precision Chrome Steel Bearing Power Transmission: Reliable and High-Quality Products by Guillo Tilden

I haven't tested them to a .001 gram consistency as I would test smaller balls where a thousandth of a gram can make a big difference. They look very nice, come in a fairly sturdy case and are oil coated to resist corrosion. Make sure you clean them THOROUGHLY before using them so you don't run into any lube sensitivities when using them as I assume they are coated in a petroleum based lube that doesn't mix well when you use one synthetic lubricant. They are very useful for any number of projects.