40s vintage watch mens Hertig ref. 8391 manual wind Certina cal. KF 320B serviced

Charles Hertig was a watchmaker active in Portugal during the 1930s to 1950s. He established the Hertig brand, which gained popularity in the country. Hertig collaborated with Certina, a renowned Swiss watch manufacturer founded in 1888, using Certina Swiss movements in his watches. This partnership resulted in pieces that combined Swiss engineering with Portuguese design.

Case:
o   Chromed with back in stainless steel (recently re-chromed) ref. 8391 serial 673939
o   Fine condition with strong geometry
o   33mm without crown / 39mm lug to lug  / 9mm tickness / 17mm width 
o   New generic plexiglass 
o   New generic crown
 

Movement:
o    Mechanical manual KF 320B -  serviced by watchmaker on March 2025
(movement was disassembled, washed, lubricated)  

 
Dial & Hands:
    o Untouched with evident marks/ signs, namely from 12 to 3 o'clock
blue hour/minute hands and golden second hand

Bracelet Material: 
  o New 18mm dar green perlon nato (military style)
 
Conclusion / Condition: 
Nice vintage piece, in good working condition…

please see photos as they are part of the description.
No box or pappers, no water proof test, sold as is, any question feel free for ask...
Keep in mind that it is a vintage watch, it is normal to be 1/2 minute early or late
wrist-treasure