Extremely historically important and also best of Longines design. Difficult but serviced with all original parts from WoStep watchmaker this is keeping COSC specs. The ESA Longines movements have been upgraded to 28800 BPH, these Longines used ESA movements had a short lifespan. Historically important like the Beta 21 for having the worlds first electronic controlled balance wheel ever. The lobster Longines bracelet as all the original links. 38mm without crown. Signed Crown.