Focus on the manufacturing and production of pen testing equipment------writing circle meter.It can be used to detect roller-ball pen tips such as: ballpoint pen refills, ballpoint pen refills, and gel pen refills.It can also be used for the detection of fiber markers (whiteboard pens, watercolor pens, highlighters).The underlined handwriting includes circles and a "Z".And related equipment, such as pen refill pressure reducer, ink output data recording system, refill slip meter, pen writing "8" machine, etc.