2 Off Resistance Boxes Type D372-A, 0 to 1101 Ohm variable in steps of 0.01 Ohm, Serial Nos 142362 and 142363, by Muirhead & Co Ltd, UK, c1955, used with extensometer equipment for strain measurement in the Structural Engineering Laboratory of Imperial College, London 2 Off Resistance Boxes Type D372-A 1955