Incredibly rare 'Raid Block' number used in RAF filter and sector operations rooms during the Battle of Britain and beyond to display important information relating to the strength of an enemy raid. The raid block itself was normally positioned at the head of the plotting path and provided information such as strength, height and whether the aircraft were 'hostile', 'friendly' or 'unknown'. This number '4' is printed in white on some form of early red coloured plastic and measures approximately 20 x 13mm. This type of coloured tile was used to indicate the strenght of the raid and It would have been positioned on the raid block along with other tiles representing height, raid serial number and so on. Please note you are buying one single number tile, other numbers, the block and map etc. are shown for illustrative purposes only. Note also that the tile is clearly not intended for use with the raid block shown and would have been used with a different one (various styles exist to our knowledge). We have a small quantity of these small white on red numbers available. A fantastic opportunity to create a small Operations room display. If you are lucky enough to own a Sector clock then this is a must have item. Stock code M21702b.