Ophthalmoscope Head Coaxial.

Features:

Halogen HPX lamp provides 30 percent brighter, whiter light output for true tissue color and consistent, long-lasting illumination
Coaxial optics produce a shadow-free spot, easier entry into undilated pupils, and a larger field of view
Polarizing filter virtually eliminates corneal reflection
Red-free filter may be used with any aperture
18 unique aperture / filter combinations for greater versatility: micro, small, and large spot sizes, cobalt blue filter for corneal exams, fixation target, and slit aperture (all on a 6-position, continuously rotating aperture dial)
Red-free filter, polarizing filter, and unfiltered Halogen HPX on a 3-position switch, each position can be engaged with each of the 6 positions of the aperture dial, for a total of 18 possible combinations
Sealed optics keep out dust and dirt for years of maintenance-free operation
Rubber brow rest prevents scratching of eyeglasses
28 focusing lenses with a range of -25 to +40 diopters
Replacement bulb Welch Allyn part# 04900-U
For All Welch Allyn 3.5 V Handles.

Singles.

Ophthalmoscope Head Coaxial by Welch Allyn