A brief and easy to read description summarizing a few of your key medical facts such as blood type, allergies, hear conditions, etc. can be invaluable to ensure that you receive proper treatment. Don't forget to add an ICE (in case of emergency) phone number so that a loved one can also be contacted.
The aluminum capsule is great for carrying medication or extra instructions along with your dogtags. Use for pills, money, tinder, weed or anything you need to keep dry.
The key-shaped knife, is ideal as part of an every-day-carry item on your keyring.