This thing is a mounting plate to fit a Manfrotto 141RC quick release head.

It has an alignment hole and pilot hole so you can fit anything to it.

I have a Manfrotto tripod with a 141RC quick release head that sits around my workshop most of the time without a camera mounted to it.

This thing will allow me to mount other things on the tripod such as a webcam.

There is a 3mm hole in the centre of the plate that can be drilled or modified to suit whatever you want to mount.