13 13CH 13CH 1P One pusher 13CH 2P Two pushers 15CHT 15TL 1872 Two register. 1873 Three register. 24 hour option. Also known as Cal 861 when used by Omega.

1883 Three register plus moonphase 2220 2310 Known as Cal 321 when used by Omega, Cal CH 27-70 when used by Patek. 33-3 CHRO 5100 CH27