Rangefinders can work through the glass because they emit an infrared laser that reflects by the glass and back to the rangefinder. The rangefinder then measures the time it took for the laser to bounce off the glass and back to calculate the distance. It makes rangefinders very useful for measuring distances through windows or other types of glass. However, there are some limitations to using rangefinders through the glass. The quality of the glass can affect how well the rangefinder works. For example, if the glass is dirty or scratched, the laser might not be able to bounce off the surface properly, and the distance measurement will be less accurate. Rangefinders only work with flat surfaces. If the surface is curved, like a car windshield, the laser will not bounce back in a straight line, and the rangefinder will not be able to get an accurate distance measurement. Overall, rangefinders can help measure distances through glass, but there are some limitations to keep in mind. Make sure to clean the glass surface before using the rangefinder and avoid using it on curved surfaces. Enjoy 3D archery with this list of +100 rangefinders.