This is a Brooklands Aero screen - a popular 'performance' item for motor enthusiasts between the wars
As it's name suggests, it was originally intended for aeroplanes. It was often found on RFC/RNAS aircraft in place of the 'standard' item, Pups for instance used them
Does anyone know of an easily obtainable 1:32 version for a Sopwith Pup I'm building?
Richard