Certina (Kurth Frères SA) is a underestimated brand that made great quality in-house movements right up to the quartz crisis of the 1970’s. A cool thing about Certina is that you can date your watch by looking up the serial number.
Pre Turtle back (58-60) Certina DS. In-house claibre 25-36. Very good condition. Serviced by me in Febuary 2018. Case size 36mm w/o crown. Asking Price £ 580