The black handle on the left side of the image.
This tool is used to make decorative lines on leather.
The spacing between the line can be selected from 1.0 mm, 1.5 mm, 2.0 mm, and 2.5 mm.
It is made by hand, not by machine, so there may be an error of about 0.1mm.
It is generally used in leather by heating in an alcohol lamp.
Used to draw lines and press them simultaneously.
Please check the video below for the link.