Taidacent Hollow Slip Ring Rotary Electrical Contact 2/4/6/12 Wires Collector Ring Conductive Electric Motor Slip Ring Rotating Connector (6 Wires 10A Inner Hole 12.7mm OD 54mm) - Amazon.com
Slip ring - Wikipedia
Rotary slip ring connectors — what are they used for?
Pancake slip rings | rotarX
ROTOCON Rotating Electrical Connectors | Slip Ring Alternatives