Bicycle Frame Lock
Based on the idea of the "detachable faceplate" for car stereos, this bicycle frame lock about 2 1/2 inches long, is actually a small but critical part of the bike's frame. It has a 5-number combination lock. Without it securely fastened, the bike frame essentially has a "hole" in it and will collapse when someone sits on it.
Made of steel or titanium, this tubular lock is highly portable and can be taken anywhere. In combination with a strong, standard bike lock, it will thwart any thinking thief. What good is a bike with piece of the frame missing?