This is the star styli #A-5555-3843. It has an M8 thread, stainless steel stem, and a ceramic ball including certificate.
|Overall length (L)||135.0 mm|
|Base Width (DG)||24.0 mm|
|Ball diameter (DK)||20 mm|
A-5555-3843 | M8 stainless steel Datum sphere with ceramic ball | M8 | Renishaw