Webley signal pistol designed to be mounted onto a bracket fixed to the walls of an aircraft or other surface ( mounting bracket missing ) the One & half inch round had to be inserted first, after firing, the gun was removed from the bracket and reloaded. The pistols fired coloured flares, Either when in distress or for identification purposes. An aircraft fired on would fire the "colours of the day" a combination of two or more colours, changed daily - to prove that they were friendly. There is some evidence that RAF bomber crews were told the German colours of the day, information presumably obtained via the code-breakers at Bletchley Park.