This is the M4 disc stylus #A-5000-7596.
Disc styli are designed to inspect undercuts and grooves within bores which may be in accessible to star styli. A range of disc styli offers a ‘radius end roller’ to enable groove width measurement..
|Diameter (A)||30 mm|
|Diameter (G)||21.0 mm|
|Width (B)||2.2 mm|
|Disk material||Silver Steel|