This Swiss Military Optical Rangefinder is a classic example of what's known as a coincidence rangefinder (aka telemeter). Strictly mechanical and optical in its operation: No batteries, no power, no computers. Instead range is calculated by aligning two images (each "end" is actually an independent scope) and viewing the combined image through the single eyepiece in the center. The closest U.S. military analog is the Model 1916 Rangefinder, which operated on the same principles. This Rangefinder calculates ranges up to 20,000 meters (12.4 miles). In practice, it would have been used for calculating artillery distances in order to accurately shell enemy positions (and hopefully not your own.) Still works for all kinds of field uses, and stands as quite the collection piece on its own. 11.25x magnification Find ranges up to 20,000 meters (12.4 miles) using right thumb control Dual range scale windows Hermetically-sealed for weather protection No batteries required Includes hard-shell storage canister Includes both ground and table tripods Includes lathe board for field calibration