Dụng cụ kiểm tra xúc giác - Touch Test Tool (2-Point Discriminator)

TTT v01 - A 2-point discrimination tool to test for touch sensitivity.

Used in fields such as occupational therapy and general health assessment.
The testing points are at a distance of 2, 3, 4, 5, 10 and 20mm, for a wider field of application.

Update: Added a second variant with testing point distances of 2, 3, 4, 6, 15 and 20mm, as requested by GregooryPEnn_1104574

The center hole is chamfered and rounded to provide a nice grip when held between thumb and index finger.

Three M2 holes with 0.2mm tolerance to screw the three parts together.
4mm M2 nuts on the back are recessed.