Unit Colour Patches (or simply known as Colour Patches) are worn on the slouch hat in the Australian Army to indicate which unit they are from. Unit colour patches are approximately 40mm x 40mm in size and have a large variety of colours and shapes to distinguish them. While some are recent creations many date back to World War I, when on 8 March 1915 1 Division Order No 81 was issued at Mena, Egypt authorising their creation.