Nikon COOLSHOT 40 Golf Laser Rangefinder HYPER READ provides quick and stable measurement response, in approx. 0.5 second, regardless of distance to the target. Increment Reading: 0.5 yards, Eye Relief: 18.3 mm. Incredible ranging capability (8-650 yards), reported in  yard increments, with an accuracy or +/- 2  feet, Diopter Adjustment: +/- 4 , Power Source: 1 CR2 Lithium Battery, Objective Diameter: 21 mm. First Target Priority technology quickly and accurately identifies the flagstick from the background. Class 1 laser product, power output not exceeding .0975 milliwats Push and release the POWER button for 8-second continuous measurement scanning, allowing quick measurements to multiple targets. Material type: Metallic fiber