This is the star styli #A-5555-3844. It has an M8 thread, stainless steel stem, and a ceramic ball including certificate.
|Overall length (L)||140.0 mm|
|Base Width (DG)||24.0 mm|
|Ball diameter (DK)||25 mm|
A-5555-3844 | M8 stainless steel Datum sphere with ceramic ball | M8 | Renishaw