Prevents glare through the lens and reduces the light that’s reflected out. The best anti-glare treatments in order are fully multicoated, multicoated, fully coated and coated.
Multi coated
Prism/Mirror binoculars
PrismBinoculars
Image quality
Lens diametre
The larger the diameter, the more light is captured. A diameter of 30 mm suffices during day-light conditions, but larger lenses are required during low-light conditions.