Used only once. The rubber coating around the front part become "sticky" and was cleaned off with an aggressive cleaner that removed some of the brown paint. Tested and works properly. 

Firearm Nikon RifleHunter 550 Laser Rangefinder This Nikon RifleHunter 550 Laser Rangefinder in brown finish comes in a black nylon carry case and features Nikon's ID (Incline/Decline) technology to compensate for bullet drop over virtually any shooting angle. No more guessing about holdover, just fast, accurate and consistent reads that get you on target quickly when seconds count. Other features includes 6x multicoated optics, an eyeglass-friendly 18mm of eye relief, 100-percent waterproof and fogproof construction; and a maximum measurement of 733 yards and you have a comfortable, powerful range finder that leaves its competitors in the dust. Designed and engineered specifically for the rifle hunter, the device measures 1.5 by 2.7 by 5.1 inches (W x H x D) and weighs 6.3 ounces. Includes manual.ZB8319 251 SWW