It won’t make your bag any havier, and your dentist will be thankful if you will use it, even when outside — plus it has a lot of potential uses in case something bad happens. You can use it to secure bandages, cut food, make an emergency shoelace, catch a fish, or even restrain somebody. While it’s so small and useful in everyday life, you’d never know how many potential uses it might have if you find yourself in danger.