I acquired these after thorough market research and I can say that I am extremely satisfied. In binoculars, the first number refers to magnification and the second to the diameter of the image you observe. Having no idea about optics (a branch of physics), I thought that the higher the magnification, the better. However, things are not exactly like that. Especially for prolonged use, you need a large exit pupil (e.g. 25/8=3.125) so that the image is not dark and shaky, especially if you want to observe celestial bodies at night (although this also depends on other factors). That's why it's worth investing in 8x25 or even 8x42 and not in 10x21 or 10x25 which are typical values for compact binoculars. These specific ones have a comfortable eye relief of 15mm and a minimum focusing distance of 1.5m to observe objects (e.g. insects) at close distances. They feature good quality BAK-4 lenses and not the inferior BK-7, which have various filters including phase coating that shows colors better. They are waterproof and do not fog up thanks to the gas inside that prevents moisture from entering. Their most important advantage, however, is their small size and especially their low weight, allowing both young and old to handle them for a long time.