I looked at the cards at MajorSurplus. They are very basic and I personally found them inadequate. This is another effort at "milthink" trying to make learning appealing. Remember the comic book training manuals? For the size get a SAS GEM. I would construct cards with the more detailed tables of information, such as a wind chill chart. Even that I found superfluous in Alaska. When your rifle's primer won't detonate due to the cold and your nose hairs fall like icicles it's no time to be calculating measured temps ! Now flash cards as a training device are another idea ;O)