... 20mm object lens. waterproof design.Hunting uses. golf range finder (JCS501 with 6x Magnification optic system and any color change is ... .5-volt battery; includes case and strap Product Descriptionthe lanhai JCS501 is the smallest, most compact laser rangefinder of its kind ... yards· Accuracy: ± 1 yard How a Laser Rangefinder Works ?lanhai JCS501 rangefinders use an invisible, eye-safe Class 1 Laser beam ...