This is a super example of an Audemars Piguet dress watch featuring their legendary VZSSC movement, that is their VZ movement with the centre seconds. This ebauche or base movement was used by a number of high end firms, both for chronograph or calendar watches and also for high precision time-only watches as is the case here. The base movement was made by the Valjoux and then finished to an extremely high standard by Audemars Piguet's watchmakers. 

There is a great deal of hand polishing and refinement visible on the movement, one detail I especially like is that the teeth of the winding wheel has polished faces - this is the silver wheel just above the "Adjusted to temperature and four (4) positions". This would have relatively little, if any, discernible benefit to the winding of the watch, but clearly for the Swiss master craftsmen it was important that attention was paid to even this minor aspect of the movement.

Another area where the very high level of detailing is visible is on the pallet bridge, beneath the balance wheel - this bridge has been black polished to create a flawless mirrored surface; You can see the same finish on the components of the swan-neck regulator on the balance cock.

There is an excellent introduction to these movements and some details of the variations that exist here:
https://www.stetzcowatches.com/2018/12/28/origins-the-13-ligne-valjoux-vz-movement/

At this time Audemars Piguet's output was relatively small and they didn't really produce consistent models or references from year to year, more or less each watch was a one-off. This example is, I think, a really handsome and timeless piece with tyhe original white dial in superb condition. The 18 carat gold case is an excellent, wearable size at 35.5mm diameter excluding the crown. Fully serviced and regulated and ready for someone to wear and enjoy. 

A really special and rare watch for someone to treasure and enjoy. 

Case diameter: 35.5mm
Case material: 18 carat yellow gold
Strap width: 18mm
time keeping: superb!