The Kryptonite Lock is a brand of bicycle lock. It is used by the bicycle owner to fix his cycle to a pole or fixture when he leaves it in a public place. The lock is made of hardened steel bent into a U shape. This lock was first created in the early 1970s. At that time the only way to secure your bicycle was to use metallic chains, but they could easily be cut using bolt cutters leading to many cycles being stolen. It is at this point of time that this new design came about.