For sale, a high-precision arc protractor for cartridge alignment.
This protractor is made of 3mm high-quality acrylic, coated with a yellow film, and high-precision laser-cut and engraved.
The first picture is for reference only; the real protractor looks like the one in the second and third pictures.
The arc protractor is the most accurate protractor for cartridge alignment; this one is designed for the following Thorens tonearms:
TP11 MkIII
TP16 MkIII
TP16 MkIV
TP21
TP28
 
The geometric features are compliant with Thorens specifications; see the first picture.
 
It is supplied with detailed instructions.
We also make custom protractors to the client's specifications.