Set time format from 12 hr to 24 hr for casio LA670W

depends on your use of watches and the environment you tend to be in. If you are somewhere that allows you to see whether there it is day or night, than using 12 hr setting will work just fine. However if you're in a place that keeps you secluded and you are not able to determine whether it is day or night than 24 hr. setting will help you keep track of not just the time, but whether it is day or night.

click the link below to download manual
http://support.casio.com/en/manual/manuallist.php?cid=009

How to Set Casio Watch

specifically step 6 below for your answer

Setting Instructions for Electronic Watches

Casio electronic watches feature many different modes ranging from timekeeping to stopwatch. The M button controls the modes. Here is how to set time on a digital watch such as models 1632 and 1813:

1. Press the M button to get into the Timekeeping mode.
2. Select the seconds digits by holding the A button down until the seconds digits flash on the display.
3. As the digits flash, press the C button, which will reset the seconds to 00. On some watches such as GW-500A, a stop/start button is used instead of a C button.
4. Press the M button and change the selection in the order of seconds, hour, minutes, year, month and day. Proceed in that sequence to change information to the current time and date.
5. As the sequence progress, digits flash when selected. Press the C or stop/start button, to increase a selected number or the B button to decrease it. Hold down either button to increase the speed of the selection change. All time and date functions are set this way.
6. Press L when any digit is selected to switch between 12-hour and 24-hour formats.

Write down the four-digit module number from the watch back, and go to this link for full info in PDF format:

http://world.casio.com/wat/download/en/manual/

Good luck, Bill

Actually, the watch has 3 buttons -- "Light" being the 3rd one. Press Mode until a number in the time mode begins flashing. Then press the Light button to get it to the hour indicator. Use the 12-24 Hr button to set it to the current hour. Then press the Light button again to get it to the minutes section. Again, use the 12-24 Hr. Button to set it to the next minute coming up in the current time. Then push the Light button again. This will bring up the seconds indicator. At the precise time the minute you set before begins, hit the 12-24 Hr. button, and the indicator goes back to zero and begins ticing away. Then hit the Mode button again until the watch is in the current time mode. Hope this helps. I use Internet time to set a precise time.

Follow this link and get instructions:

http://world.casio.com/wat/download/en/manual/

Rate me, please.

Go to:

http://ftp.casio.co.jp/pub/world_manual/wat/en/qw2016.pdf

Full user manual and instructions there to download.

Use this page to download a copy of CASIO watch manuals in PDF format. To download a PDF file, enter the four-digit (or three-digit) module number marked on the back cover of your watch.

http://world.casio.com/wat/download/en/manual/


You will need a pdf reader on your pc, you will find all instructions in there.

set the digital dual time to any time you want