If the X-Finger looks like a prop from The Terminator, relax. It isn't out to kill you, and it isn't robotic. In fact, it's a mechanical prosthetic finger so effective it provides articulation as fast and flexible as the real thing.

Invented by Dan Didrick of Naples, Florida, the device has no batteries, electronics, servos or actuators. Instead, each digit incorporates a simple mechanism which, when pushed by the surviving part of the wearer's finger, curls a set of artificial phalanges.

"Having a body-powered device leaves little room for mechanical failure," Didrick said, adding that there aren't any robotic medical alternatives. "Many people assumed a device such as mine already existed."