IOR-Valdada Binoculars are of the highest quality in the world. The best glass in the world coupled with the best lens coatings in the world makes looking through these an absolute dream. A ONE-TIME focus system is used and diopter adjustments can keep your settings for quick and easy viewing. Lifetime warranties and unmatched quality puts theses on the "Must Have List" when it comes to optics. Once you look through a pair of IOR binoculars it will be hard to ever look through any other piece and be as pleased!