The term derringer is a generalized misspelling of the last name of Henry Deringer, a famous maker of small pocket pistols in the 19th century. Many copies of the original Philadelphia Deringer pistol were made by other gun makers worldwide, and the name was often misspelled; this misspelling soon became a generic term for any pocket pistol.
The original Deringer pistol was a single-shot muzzle loading pistol; with the advent of cartridge firearms, pistols began to be produced in the modern form still known as a derringer. A derringer is generally the smallest usable handgun of a given caliber. They were frequently used by women, because they are easily concealable in a purse or as a stocking gun.
The Marushin Derringer serves the same purpose as the real steel; one of the smallest Airsoft weapons, its tiny size and super light weight make it the ideal choice for the back up for your back up, a boot or hidden pocket gun.
This Marushin Derringer is a 6mm weapon; cocking the hammer and pulling the trigger shoots the top barrel, re-cocking and shooting again fires the second lower one.