ATN 7x30RF Omega Class Range Finder Military / LE / Marine Binocularsas well as all marine binoculars use an optical grid rangefinder, not a laser
rangefinder. An optical grid rangefinder uses a reticle which requires you to know the height of the object in question, then do mathematical calculations. This is an old technology that survives in marine binoculars more out of tradtion than usefullness. To be honest, it is impractical for field work.
You calculate range according to the following equation. It does not matter what units you use (feet, yards, meters, kilometers) as long as you use the same unit for all variables.
DISTANCE = ACTUAL HEIGHT DIVIDED BY SCALE (RETICLE) HEIGHT X 1000