Has any1 ever heard of, know how to make them, or where to buy smoke bombs that u snap like glow sticks and they smoke?

a friend i meet on a recent cruise told me that his friend buys then or makes for use in air soft wars but that guy keeps it a secret. any feedback would bee nice they would be nice to have and hopefully cheap and easy to make or buy. anything would be nice!!!!!!!!!! THX!!!!!!!!!!!!!!!!