ETA/Unitas Caliber 6503

Manufacturer	ETA/Unitas
Caliber Number	6503
Base Caliber	ETA/Unitas 6497
Movement Type	Manual wind
Size (lignes)	16.5”’
Diameter	36.6mm
Height	5.0mm thick
Jewels	15 or 17
Vibrations Per Hour	18,800 bph
Shock System	Incabloc
Winding Direction	Uni-directional
Hacking?	No
Functions	Hours, minutes, small seconds at 9:00, date
Country of Manufacture	Switzerland
Known Brands	Add your watch in the comments below…

ETA/Unitas caliber 6503 is the rarely seen version of the manual wind ETA 6497 with a date complication.

The 6503 was produced in the 1960s and is currently discontinued. It is hard to find watches powered by this movement, if you have a timepiece with the 6503, please share it in the comments below.

Modern Usage:

There is a German watch company called Guinand which still produces a manual wind pocket watch featuring a calendar window at 3:00 (Model G-1996S). Guinand’s caliber HS81 is based on the ETA/Unitas 6503, but with modifications created by Helmut Sinn, including a central sweeping seconds hand (instead of the standard 6497 small seconds at 9:00), as well as a hacking mechanism. It is likely that they had access to new old stock 6503 movements for this model.

Additional Resources:

• ETA/Unitas 6497 VS 6498
• ETA/Unitas 6497-1 VS 6497-2
• ETA 6497 Disassembly