simplemente miré en Rannft:
Longines 847
Features
manual wind
Data
10.5''', Dm= 23.3mm, H= 2.5mm
17 jewels
f = 21600 A/h
power reserve 40h
Remarks
micrometer regulator
family/generations:
standard regulator, Kif-Flector:
420: sub second
428: no second
micrometer regulator, Kif-Ultraflex:
846: sub second
847: no second
differences not known between 847, 847.4
Example, year: signature; shock device
1977: 53293727, Longines Watch Co Swiss, 17 Jewels; Kif-Ultraflex
(Longines 847.4)