Renishaw's stylus naming protocol makes it simple to identify a stylus by its name as well as by its part number.
The examples below explain this and define the abbreviations used.
M2 STY D2R L20 EWL14 d1.4SS
M2 thread straight stylus with a Ø2 mm ruby ball, 20 mm in length, EWL of 14 mm and a stainless steel Ø1.4 mm stem.
M2 STR D2R 5BALL L19.5 S32
M2 thread star stylus with a Ø2 mm ruby ball. It has 5 balls on the star and has an overall length of 19.5 mm (from the centre of the ball to the rear of the star mounting face when assembled on a probe). The span of the star cluster is 32 mm.
M2 DSC D18 SLVS T2.2 L2.6 BR-Y
M2 thread disc stylus with a disc diameter of 18 mm. It is made from silver steel with a disc thickness of 2.2 mm and a length of 2.6 mm. BR stands for balls/rollers followed by yes (Y) or no (N).
M2 CYL D3 SLVS L13 EWL4
M2 thread cylinder styli, with a critical measuring element of Ø3 mm made from silver steel. It has a length of 13 mm and an EWL of 4 mm.
M4 EXT L15 d7 SS
M4 thread extension with 15 mm length, Ø7 mm, made from stainless steel.