One star deducted because one or two bearings are very noisy. Everything works, but not quietly. They all roll, but not the smoothest. So for the money this is a good deal. Note: I cleaned and oiled them before using them on the 3D printer. No solids, just a tan dirt applied at the factory to prevent surface corrosion. I used Super Lube synthetic silicone lube in a 3 ounce tube with a 3D printed tip (available on Thingiverse); However, I think this is too much pressure for these camps. The lube I applied actually shifted the balls, and the balls landed on the ends of the rods when I installed them. It was all my fault. Next time I'll use a milder cleaning/lubricating solution, maybe DeoxIt and some compressed air? I will definitely be using an aerosol silicone lube with a straw applicator attached to lubricate the next batch I order. My $0.02, YMMV.