Welch Allyn 3.5 V Standard Opthalmoscope uses a halogen light to get true tissue color and consistent, and for long-lasting illumination. The opthalmoscope has a rubber brow rest to prevent scratching of eyeglasses, and it's reliable and versatile at an economical price. This opthalmoscope features 28 focusing lenses ranging from -25 to +40 diopters, and 6 apertures for generalist use: small, micro, and large spot sizes, fixation target, slit aperture, and red-free filter.