Steel Serpent Kubaton
You always have your keys with you, so why not always have a defense weapon as well. This mean steel serpent kubaton looks like a harmless keychain even though the steel spike is far from harmless, but unscrew the end and it sheaths a 2 1/2" dagger that flips around and screws in the end to make it 6 1/2" overall. It's the perfect solution to never having anywhere to carry a defense weapon. Blade is made from stainless steel and the body of the item is of another metal alloy.