As with many inventions the time at which it was developed helped with its success. Manufacturing items in large quantities makes them accessible at lower prices to more people but the costs of setting up large scale production often prevents this from happening. The need for pens that wrote whilst aircraft were being flown – in times such as wartime – without ink leaking from the pen in the reduced air-pressures found at ‘flying altitudes’ - assured the company of larger orders than might otherwise have been ossible. Both the British and American airforces used them.