Flare gun

An Orion-brand single-shot, breech-loaded, 12 gauge flare gun. Its design is typical of commercially available flare guns, with a high-visibility red casing.
Patel Gun
A single-shot, 26.5/25mm flare gun manufactured by Patel Ballistics. It is chambered in a different caliber from the Orion flare gun.

A flare gun, also known as a Very pistol or signal pistol, is a large-bore handgun that discharges flares, blanks and smoke. The flare gun is typically used to produce a distress signal.