Very rare German Sphygmomanometer from the turn of the century. An aneroid sphygmomanometer (for taking blood pressure). A very rare German model Tonometer nach Dr. von Recklinghausen, from the beginning of the 20th century. The device was made by, Med. Warenhaus Akt. Ges. Berlin. It includes a pressure measuring scale in units of millimeters of mercury in a range from 4 to +300, also a scale in units of centimeters of water in a range from 5 to +400. The scale dials can be rotated 360° so the device can be zeroed.