Ear examination started with a "shoe horn" model speculum. This was followed by bivalve / trivalve specula which was used for all body cavities. The first scientific ear examination was conducted with a bivalve specula. Two models were famous those days. The first one being Itard and the other one being Kramer. Wihelm Kramer devised this bivalved speculum to examine the ear canal. Kramer speculum is the mother of all bivalve speculum and the currently used Hartmann's speculum is a modification of Karmer's speculum.
When closed the blades of kramer's speculum forms a conical tube split into two halves through its long axis. Each half mounted upon one end of a forceps blade. The blades are kept closed by a spring, and can be opened to any desired extent by pressure on handles. The blades are usually thin about one and a half inches in length and 4 mm in breath. The internal diameter would be about 12 mm at its base.
Kramer's aural speculum