The 2 mm Kolibri (also known as the 2.7 mm Kolibri Car Pistol or 2.7×9 mm Kolibri) is the smallest commercially available centerfire cartridge, patented in 1910 and introduced in 1914 by Franz Pfannl, an Austrian watchmaker, with financial support from Georg Grabner. It was designed to accompany the Kolibri semi-auto pistol or single shot pistol, both marketed as a self-defense weapon. The name is derived from the Kolibri or Hummingbird, which is among the smallest of birds.