Nikon (16229) Prostaff 3I Rifle Range Finder, Black Displays in 0.1-yard Increments; Ultra-Compact Size ID (Incline/Decline) Technology; Large Ocular Lens True 650-yard Ranging Capability; Easy-to-View Uncluttered LCD Display Tru-Target Technology; Single Button Operation; Power Source: 1 CR2 Lithium Battery Measurement Range: 8 - 650 yds; Angular Field of View (Real): 7.5 Use for Gun Hunting, Bow Hunting, Target Shooting; Objective Diameter is 21 mm Size: (Length x Width x Height) 4.4 x 1.4 x 2.8 inches & Weight w/o Batteries: 5.6 oz