This is a video of a guy who made a fully functional replica of Ezio's hidden blade from Assassin's Creed: Brotherhood. It's activated by a ring worn on the finger and locks into place once extended, but retracts with another twitch of the finger. Obviously, I must have one. No -- two. Plus Wolverine claws (I live in a really bad part of town).
Based on a dual action Out The Front (OTF) Mechanism with a ring driven ratcheting pulley system to index the OTF Mech.
Blade locks in both the extended and retracted positions and can be extended and retracted regardless of arm orientation (no gravity/arm shake required).
You just have to see it in action, it's amazing. What's not amazing is guy's camerawork, which doesn't do the blade anywhere near the justice it deserves. You made a functional hidden blade, now make a f***ing tripod. Amirite guys? High-five! *SNIKT* Haha, you're right-handed anyways.
Hit the jump for the blade (which is actually plastic because that's how good dude is at assassinations) in action.
Thanks to Jason, who's never performed an assassination with a hidden blade before but did clear a room out once with a silent but violent fart and will probably never send me another tip.