Vanguard Ocean 10x50 Full-Size Waterproof Binoculars The transmittance of optical filming glass optical lenses reaches 99.5%. It has clear imaging effect and stirring visual effect, it is particularly suitable for young people interested in astronomy. The lens is made from aluminum alloy and big-caliber non-dispersive and superior optical glass-ZF4. The lens is plated with multi-layer green film. It will not damage the vision even if use it a long time. The primary lens barrel is made from metal material and by using German latest technology. Allocated with environmental painting technology, it has the high quality and it is durable. The thickened aluminum alloy support is firm, stable and durable. The height can be adjusted freely for you observing the star better..High-quality backpack, convenient to be collect the telescopes and protects the telescope better and prolongs the service life..Optical Tube Type: Refractor The Gskyer possess a 70mm aperture and 400mm focal length