[Premium Construction] Features manual adjustment, durable all-metal structure, and multi-layer mc coating for optimal light transmission and image quality. [Super Telephoto Zoom] Offers a 420-800mm zoom range, which can be doubled to 840-1600mm when paired with a 2x magnification mirror. [Widely Usage] Ideal for various photography needs, can be easily installed on a telescope to observe the moon or on an ef-s mount camera for capturing faraway subjects. [Versatile] For capturing distant landscapes, wildlife, concerts, and birdwatching with precision and clarity. [Enhanced Magnification] The 2x magnification lens effectively doubles the length and magnification for sharper and closer shots.