The Shimano sprocket for CS-M9100-12 is an original spare part for the XTR 12-speed cassette in the increments 10-45 or 10-51. It is one of the first two sprockets with 10t or 12t. All these sprockets are made of steel.
The 10 and 12 tooth version is only available as a set, which can also be used for the following:-
Fits Micro-Spline 12-Speed