Professional Optics: The fixed magnification of the compact rifle scope is 3x, the objective lens diameter is 30mm, the eye relief is 76.2mm-88.9mm, and 1 click is 1/2" at 100 yards. This rifle scope is only 120 mm long, making it easy to carry and operate. It is active in outdoor sports activities. Broadband Green Film: Fully multi-coated lenses provide over 90% light transmission, vivid images, and exceptional color contrast, providing bright and clear images. The scratch-resistant coating protects the external lens from scratches, oil, and dirt. Comfortable Viewing Distance: 76.2mm-88.9mm eye relief. Crystal clear optics provide a comfortable viewing distance of 3.0-3.5 inches. 5-level Brightness Adjustment: The black dot is always displayed. For easy viewing of the dot at night or in poorly lit situations, there are 5 levels of brightness adjustment for both red and green dots. The battery type is CR2032 (sold separately). Rugged, Waterproof, Fog-proof, and Shockproof The rugged construction withstands recoil and impact. It is completely sealed and 100% nitrogen-filled, making it resistant to fog and rain.