12.5mm 300Rpm 6 Wires CIRCUITSx2A Capsule Electrical Slip Ring for Monitor Robotic Electrical Test Equipment 1Pcs

I haven't used it yet and I'm sure it probably will work fine but it's a lot smaller than I had anticipated.

Worked as described

It works, feels smooth, and there’s continuity across each of the six wires (not between them). Now, you mount the flange to either the stationary or rotating assembly. The other side is *not mounted to anything,* the wires are routed and boom, you can transmit power across an infinitely revolute joint. If you want to use this with a motor, it’s possible but not in the way other reviewers think it is. There are slip rings meant to be used with motors, they’re called Hollow slip rings. I use this slip ring within bearings, and my rotating assembly is driven by a ring gear and a stepper, so I don’t need the hollow type

One part has a flange with holes which makes it easy to attach so a solid piece, but the other moving part is incredibly small, like ~4mm across and ~4mm high so it's almost impossible to attach something to it in a secure way.

The piece is beautiful and useful. But it is very difficult to assemble any thing to the centre rotating part. The outer part can be easily mounted with 3 holes. But I could not mount the rotating part in the center to the shaft of a motor. And I gave up on doing my project.