20X50 high quality coin operated binocular

BIJIA 20X50 Binocular

Knowledge spread

Prism material:BAK4 is not about the lenses, it is about the prisms that fold the light path inside the binoculars. BAK4 prisms are generally considered better because they give a perfectly round 'exit pupil' (what you actually see). 

Lens coating: FMC( fully multi-coating),the antireflection coating is the action of the lens, the anti-reflection film is known as antireflection film, which is to try to suppress the effect of the reflection sheet glass lens, loss of light quantity is reduced, as much as possible so that the incident light through the lens, and therefore the anti-reflective film layer antireflection effect can produce, while multi-coating, the lens will not reduce the rate of identification, nor damage the color reproduction. High tech multi-coated, high permeability rate, image clearer.