This traditional older model features an enclosure so that when the speculum is introduced into the ear canal a closed air chamber is created between the external canal and the interior of the otoscope (closed system).
The standard diagnostic otoscope features coaxial illumination which can be derived either from an incandescent bulb (2.5 V system) or a halogen light source (3.5 V system).
By attaching a valveless rubber bulb to a side arm or opening in the enclosure, pneumatic otoscopy is possible.
The excellent illumination combined with the wide bore of the speculum makes the Welch Allyn 3.5 V halogen standard diagnostic otoscope
The Welch Allyn 20 2000 is the otoscope of choice for both the routine examination of the ear and pneumatic otoscopy.