Answer:
Spragues have 2 tubes from the earpieces all the way down to the bell. The bell is two-sided with clear diaphragms on both sides. You can find a picture at...
http://www.mdfdirect.com/1_4.htm?gclid=c...
If new, look at the box it came in.
If old, compare it with pictures in a medical supply catalog or on the 'net.
