Also known as a kubaton in its genericized Model, the Kubotan is usually a name-brand self-defense keychain that originated in the sixties. Find out more about the Kubotan. The Personal alarm is supposed for being added to the keychain, when the opposite two devices would make a keychain somewhat bulky. https://elliotgkkmj.blogdal.com/32164960/the-smart-trick-of-kuromi-keychains-that-no-one-is-discussing