With porro prism design,anti-reflection coated lenses and large light throughput these binoculars are intended primarily for marine use. A key features is the individual focusing function that, after a one-off adjustment for individual eyesight, gives the freedom to directly focus on a desired object without manual focusing! Perfect in rough seas. Rugged, robust and of course waterproof. If you should be unlucky enough to drop them in the water, ETERNA™
Marine II will float!