Swinger Type No.6. Brass metal fly buttons as used on R.A.F. battledress trousers etc. Approximately 13mm diameter. One has a small 'spike' in the centre on which the second magnetised button can be balanced. Small luminous dots on this button indicate North and South. Another ingenious gadget from MI9 issued to aircrews to aid escape and evasion. As issued and still sewn to the original card. Photos No.6 shows another example used to show the compass 'assembled' - the one for sale has not been removed from the original issue card. Stock code E21348.