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.

For example, in an 8x25 monocular (or binocular) "8x" refers to the magnification power, which means that the image will appear 8 times closer than it does to the naked eye. The "25" refers to the diameter of the objective lens in millimeters, which is the lens at the front of the monocular. A larger objective lens diameter generally allows more light to enter the monocular and can result in a brighter image. The same rule applies to all other sizes such as a 10x42, 8x42, ...

It's important to note that while a higher magnification can bring objects closer, it can also make the image appear shakier or harder to focus. Additionally, a larger objective lens can make the monocular or binocular heavier and bulkier. So, it's important to choose the right combination of magnification and objective lens diameter that suits your needs and preferences.

Check out our ZOOMR models and choose the right size for your activities HERE.