Rare WWI British Cooper Bomb Cone and Propellor - Nose Spinner

This is a rare WWI dated British Cooper Bomb cone and propellor (nose spinner) . The body is maker marked McC and date stamp of 10-17 October 1917. When the bomb was released, the nose spinner was freed to turn which then rotated a plate in the nose, which eventually exposed the detonator to a firing mechanism, which would be activated when the bomb struck a solid object. A rare find!