Convoy Calculator Watch (Blue)

This is my Convoy Calculator Watch which only has 2 functions which is Calculator and Time, The Alarm is constant when it goes off but you'll see what I mean when it is tested and then goes off etc. This one compared to my Digi-Tech works the same but the settings are in different sections and is slightly more complicated but once you get used to it, it is very simple. No Chrono or Dual Time as the cover might be from a watch that is mean't for Dual time but since the watch is Vintage from 1984 it will be impossible to find out the right answer. enjoy