Special features binoculars

1. Waterproof binoculars: nitrogen purged or nitrogen filled internally and O-ring sealed, the nitrogen prevents oxidation and internal fogging. There are various terms to describe this feature, such as water-resistant, moisture resistant, splashproof, sprayproof, fogproof, rainproof, weatherproof and showerproof, they are not waterproof.

2. Shockproof binoculars: These binoculars are specially designed to military purpose and rugged environment.

3. Zoom binoculars:  In general, zoom binoculars optical performance is not as good as the standard binoculars or fixed focus binoculars. But these binoculars are convenient to use.

4. Opera glasses: Most of opera glasses are Galilean binoculars, which without prisms and only utilize the lenses.

5. Monocular: A monocular is one half of a binoculars

6. Astronomical binoculars: In general, these binoculars objective lenses size is more than 60mm, as the binoculars can provide the 3-D quality of the stereo image, it is better than the "flat" view from a single-ocular telescope.