This thing is a Button Guide. it is used when wrapping buttons to make traditional style buttons for period cloths, cosplay or simply decoration.

The guide can be customised to any size between 15mm and 100mm. you can have any number of divisions from 2 to 24. The divisions are used for marking the wrapping points for the button. The edge can be chamfered and the top can be dished, both help with the asthetic of the ButtonGuide although they are not essential.

To help keep the ButtonGuides organised you can include the diameter and number of ticks in the print.