Sharpening Stone - Whetstone - Large Size, Knife and Tools Sharpener - Fine Grade Marble Polishing Stone - Natural Stone - Long Lasting : Amazon.co.uk: Home & Kitchen
Sharpening Stone - Whetstone - Large Size, Knife and Tools Sharpener - Fine Grade Marble Polishing Stone - Natural Stone - Long Lasting : Amazon.co.uk: Home & Kitchen
This is a steel wire frame with two glass marbles. It was found in an old garage among various stuff. The marbles can turn inside the frame. : r/whatisthisthing