The light transmission in a monocular or binocular refers to the amount of light that passes through the device and reaches the viewer's eye. The higher the light transmission, the brighter and clearer the image will appear.

In the description of a monocular or binocular, such as 8x25 or 10x42, the numbers refer to the magnification power and objective lens diameter, respectively.

Prisms are a key component of binoculars and monoculars that help to correct the image and provide a clear and bright view. There are two types of prisms commonly used in binoculars and monoculars: Porro prisms and Roof prisms.

Binoculars and monoculars are often filled with nitrogen to prevent moisture from entering the internal components of the device and causing fogging or condensation on the lenses.

Eye relief refers to the distance between the eyepiece of a monocular or binocular and the viewer's eye at which the entire field of view is visible without vignetting or shadowing.

FOV stands for Field of View, which is the width of the observable area that can be seen through an optical device, such as binoculars or a monocular.

To adjust the diopter of a binocular, first focus on a distant object using the center focus wheel while closing your right eye. Then, close your left eye and adjust the diopter ring on the right eyepiece until the image appears sharp and in focus.

When using a binocular or monocular, it's essential to have the correct eye relief distance to prevent eye strain and ensure comfortable viewing.