We usually lock our homes and other valuables to keep them safe from burglars. However, the biggest drawback of a key is that it can be easily duplicated. To avoid this problem, mechanical engineer Dr Alejandro Ojeda has collaborated with 3D-printing expert Felix Reinert and lock designer Jiri Holda to develop a 3D-printed key called the "Stealth Key."

They have co-founded UrbanAlps, a company based in Zurich, Switzerland, and are already serving few pilot customers. The "Stealth Key" is made of titanium and designed inside out to keep many design elements hidden from view and thus prevent copies.

The manufacturing process is the same laser technique followed for making jet engine parts and turbines. A single key can be manufactured in half a day, but the machine can produce up to 850 different keys at the same time.

Each pair of keys, along with the lock, will cost you $200. In case you lose the keys, the replacement will cost just as much, and you would have to fulfill a security check. You would also have to wait an additional day to receive the replacement.