Standardized interface for the mounting of lenses, described in ISO 10935 (1996-12) Optics and optical instruments – Microscopes – Interface Type CS
The diameter of the thread is 1 “(one inch) and there are 32 threads to 1” in length.
The distance between the mechanical stop of the lens and the sensor in cross bolts in air is 12.52 mm. These are about 5mm less than for C-mount lenses.
C-mount lenses can (with an 5mm extension (C-CS-mount adapter)) be used in CS-mount cameras,
However CS mount lenses can not be used in C-mount cameras.
CS-Mount lenses are mostly used in security systems, often these are wide-angle lenses.