A metal T2 adapter that allows you to attach the Canon EOS R body to, for example, a telescope or astronomical telescope with a T2 mount.

T2 adapter that allows you to attach Canon EOS R, i.e. RF and RF-S mount mirrorless system cameras to any T2 (T-Mount) mount.
Most commonly, this is used to attach a camera to a telescope or stargazing telescope, allowing the telescope to truly act as a telephoto lens.
The T2 adapter is screwed onto the T2 thread of the optic/accessory. The camera body is attached to the other end of the adapter.
Camera mount: Canon RF / RF-S
Lens mount: T2