Features: 40mm multi coated lens with 10x to 300x magnification delivers larger field of view, and clearer long-distance viewing. Boasting BAK4 prism, fully multi-coated(FMC) quality optical lenses improve image clarity and brightness. Twist focusing ring to adjust the focal length, and the monocular is retractable to control its definition. Compact, durable, and easy to grip. Suitable for travel, birding, spectator sports, concerts, or enjoying scenery. Comes with a lanyard , cleaning cloth, and carrying case. What Are These Numbers Mean? 10-30040mm: 10-300 is the magnification, which means what you see is adjustable from 10 times normal size to 300 times, and the 40mm is the Objective Lens Size. 10-3025mm: 10-30 is the magnification, which means what you see is adjustable from 10 times normal size to 30 times, and the 25mm is the Objective Lens Size. Specifications: Material: , Metal Color: Black Magnifications: 10-300x / 10-30x (optional) Objective Lens Size: 40mm(for 10-300x), 25mm(for 10-30x) Field Angle: 3.5(for 10x), 2.0(for 30x/300x) Distance: 0.5~3000 meters Prism: BAK4 Package Size: 13.5*7*5.6cm / 5.31*2.75*2.2in Package Weight: 180g / 6.34oz Packing List: 1 * Telescope 1 * Cleaning Cloth 1 * Lanyard 1 * Carrying Case 1 * User Manual