This is the original winding stem for the Seiko Perpetual Calendar.

This stem suits among other on the following case numbers:

6A32-00L0, 6A32-00A0, 6A32-00B0, 6A32-00C0, 6A32-00D0, 6A32-00F0, 6A32-00G0, 6A32-00H0, 6A32-00J0, 6A32-00K0, 6A32-00L0, 6A32-00M0, 6A32-00N0, 6A32-00P0, 6A32-00R0, 6A32-00T0, 6A32-00V0, 6A32-00W0, 6A32-00X0

Seiko models:

SNG087P1, SNG089P1, SNG091P1, 

SNG087, SNG089, SNG091,