The Kryptonite lock is an Ingersoll Ran-owned brand of bicycle lock for securing a bicycle to a pole or other fixture, when the owner wants to leave the bicycle in a public place. It was named after kryptonite, the fictitious substance that can thwart the powerful comic-book hero Superman. The basic design, made of hardened steel of circular cross section bent into a U-shape with a removable crossbar, has been emulated by numerous other manufacturers, and adapted with variations in size and shape for other applications, locking motorcycles for instance.