Staiger Radio Controlled Clock
Two pins on rear - probably short together to reset - needs to be checked
New battery, momentarily insert wrong way round for reset
Install "Junghans MEGA" application on mobile phone
Start application and select "Set Mega Watch"
Select timezone and check current time.
Press 'Play' on the app and set volume to full.
Install batteries into clock, and place clock mechanism directly on top of the phone speaker - likely side opposite the battery.
Leave for 5 - 15 minutes, and the clock time should be set correctly.
To test whether this is really being transmitted from the phone, set a 'wrong time' in the app, and try to sync that.