Most bike locks are designed to make it harder to remove your bicycle from a rack, and they're often an effective deterrent to thieves. But when bolt cutters render them useless, the Stemlock serves as an extra layer of security by preventing a freed bike from actually being steered and ridden away.
When permanently installed on your bike, a quick turn of a key unlocks the handlebars from its front forks, allowing both to be turned independently and eliminating the ability to steer it while riding.
Its creators boast that it's far more compact than having to carry a bike lock everywhere you ride, but the Stemlock—available come August for just north of $100—is probably better suited as a secondary line of defense. A thief just looking for parts can still just toss your unridable bike in the back of a truck. But if they want it for riding, not being able to steer is one heck of a deterrent. [IXOW via Gizmag]