Set of four semi-circular bowls wedges. 

Purpose: to prevent an unstable bowl at rest from moving or falling over while being measured.

Usage: push one wedge gently across carpet towards the front edge of a canting bowl until contact is just made with the part of the bowl resting on the carpet. This will ensure it doesn't fall forwards in the direction of the cant.

Once it is securely in place, position a second wedge on the opposite side of the bowl to ensure it is not pushed backwards during the measurement operation.