A slip ring can be used in any electromechanical system that requires unrestrained.
Intermittent or continuous rotation while transmitting power and / or data.It can improve mechanical performance, simplify system operation.
And eliminate damage-prone wires dangling from movable joints.
Slip Ring has many different and alternative names such as transmission ring.

Electrical rotary interfaces, electrical rotating connectors. Electrical rotating collectors, swivels, or electrical rotary joints.

These transmission rings or rotating connectors are commonly found in many motors systems. AC electrical generators systems, and in packaging machinery, … etc.
In general, they can be used on any rotating system to transfer power, control circuits, or analog or digital signals.

As a conclusion, there are many different types and sizes available of slip rings either standard or customized depending.
On the user requirements, and the industry type, and this will lead us to the next question.

Under these technologies there is a wide range of slip rings products depending on the components.
And industries requirements, such as.
Pancake slip rings, Pneumatic slip rings, Miniature slip rings, capsule slip ring.
Mercury slip rings, Wireless slip rings, USB slip rings, Waterproof slip rings, Ethernet Slip Rings, and Fiber Optic slip rings, as the following:

Pancake Slip Rings
The shape of this slip is flat, for that, this type is also known as.

Flat slip ring or Platter slip ring, in this type, the conductors will be placing on a flat disc.

And the concentric rings will be locating on the center of a rotating shaft.

For that, this arrangement has more weight and volume, and it has greater capacitance and greater brush wear.