Though not as easy or convenient as a modern day laser rangefinder, the WWII Finnish military surplus stereoscopic rangefinder is half the price of its modern day counterparts, and just as reliable. Not only does the WWII rangefinder provide a topic of conversation and a challenge to its operator, using basic principles of prisms, mirrors and your own visual cortex you can calculate the correct range of a target up to 25,000 meters. That’s 15 miles!