Show device time
If you select 'show device time' this means the times shown on your locations will be the same time as on the device you are tracking.
For example; Johnny is in the UK on his travels and the time there is 22:00 but you're in New York so your time would be 17:00. On your locations it would say 22:00 if you select "Show device time"
Show your time
Your time simply means the time that is shown in your location, this is based on your IP address.