This is a cold war Radiation slide rule with army carrying case. The marks from the English Blundell (Radiac Calculator 6665-99-911-0060 are also found on the Dutch Army issue dark green leather case. It also has the words “rekenschijf – Radiologisch – 1 piece” on it, indication there should be 1 piece of Radiac in there. But the interesting thing is there are 2. The large one with the above number is also signed BRL (Blundell) Weymouth, England. It has a white side (for LAND and a blue side for SEA) and fits correct in the case. The smaller one has only a pink side for LAND even though the back states there should be a blue side as well? There is also Dutch text in the centre of the pick disc. It seems this was specially made for the Dutch Army but for practice use only (as stated in Dutch). The reference number for the smaller disc is 6665-110060 and also called the Radiac No 1, so also made by Blundell. Last piece of the set is a Dutch card for the Dutch Army instructing what to do in case of a Nuclear bombing (NBC or ABC). I am selling this set as I found it with all the extra’s so 5 pieces in total. The diameter of the larger disc is ca. 12,5 cm or 5 inches in diameter. There are signs of use all over but no damage. Check the attached video on how to work your vintage man tool : slide rule operation instructions!