1.Our10-30x42 zoom monocular telescope features advanced Fully Multi-Coating technology and large BAK4 prism lens, to increase the amount of light transmission and reduce unnecessary light reflection, and provide clear, Good-contrast, color-accurate images at the same time. Whether you wear glasses or not, this monocular telescope can provide a nice view during outdoor adventures and you won't be dizzy even after watching for a long time. 2.No fear of any weather, to ensure a more worry- experience. The monocular telescope is fully rubber armored providing a non-slip grip to the user. The nitrogen-filled design makes the monocular telescope multi-use in any environment. 3.The 10-30x42 zoom handheld monocular telescope also includes a cell phone holder. Smartphone adapters allow you to project images from your monocular telescopes onto your phone. The multi-layer broadband coating of 42mm wide objectives and Good-power monocular telescopes contributes to better light transmission and resolution, resulting in bright images. 4.large 42mm objective lens allows you to see farther and wider. The coating adopts FMC broadband coating and Good-quality BAK4 prism to ensure image authenticity