Cut pressed flat circle - core dark grey fibrous (pulp?), both faces covered thin white paint (?). Around edge of 3/4 of one face are numbers "0-27" with 1/4 subdivisons (weight measure?). Back face has 2 levels "54-86" around 1/3 of the edge, with "D4" opposite. Central circular hole surrounded by 3 lozenge holes. Flaking - FD. From weighing machine? See #21328.
Dia=126; th=3; inner hole Dia=13