This stethoscope is named after Horst Oertel, a German born pathologist who qualified from Yale and worked in America and Europe. It is similar in function and design to the phonendoscope but smaller. It consists of a metal chest piece to which a diaphragm is held taught by means of a threaded ring. The bell is connected by two rubber tubes to black glass ear pieces. This example dates to the early 1900s and is of French origin with a characteristically stylish leather etui.