Burrow's Monaural Stethoscope This is a monaural stethoscope of the Burrow's type. It is composed of a narrow wooden body that flares out to the earpiece. The diaphragm is almost flat, the base is ever so slightly concave and with a rubber ring around the circumference. This is characteristic for the Burrow's type stethoscope, which could also acted as a percussor. 1800-1899