With the new Calibre 916 (1969), Jaeger-LeCoultre released several Memovox references from that point and on into the 1970’s.
One of them was this reference E 872.
The new Calibre 916 offered some technical improvements compared with the previous Calibre 825;
The self-winding rotor with ball bearing, here a full circle rotor compared with the earlier bumper rotor.
Oscillator at 28.800 beats per hour (4 Hz) compared with 18.000 (2.5 Hz).
But one of the biggest progressions in view of the alarm and maintenance was the centred alarm pin. Instead of an attached alarm pin which often broke or got loose making the alarm to fail and most of the time compromise the tightness of the case, with the new Calibre 916, the alarm pin were made out of the same metal block as the rest of the case back.
Results being better and stronger sound and an alarm pin that held. Can’t remember seeing a Calibre 916 watch with a broken alarm pin while with the Calibre 825 it’s a quite common problem after 50+ years of use…