Prism monoculars work according to the Kepler telescope principle. Telescopes produce an upside-down image and have a long focal length. Prisms reverse the image between the objective lens and the ocular (eyepiece) to reduce the length of the instrument and to correct the projected image as well as to provide a longer, folded lightwave distance (optical zoom).

Includes all the standard features you would come to expect, including a focus wheel and a twist out eye relief distance adjustment.

Size matters when it comes to lenses. A larger lens will let it more light making the image brighter and bigger. 

10x optical magnification is no joke. You'll be surprised at how far you'll be able to see with this monocular. Pro tip - you can enhance the optical zoom 3 - 10 times using your phone's digital zoom capabilities. Have fun!