Compact and lightweight. Waterproof (up to 2 m for 5 minutes) and fog-free with O-ring seals and nitrogen gas. Aspherical eyepiece lenses minimize image distortion. Multilayer-coated lenses deliver superior light transmission for bright, clear images. High-eyepoint design provides a clear field view, even when wearing glasses. Click-type diopter adjustment: lets you compensate for differences in sight between your left and right eye for a sharp, balanced view. Turn-and-slide rubber eyecups make it easy to position your eye at the correct eyepoint. Rugged aluminum die-cast body: durable design with rubber armoring for shock resistance and a firm, comfortable grip. Eco-glass optics, free of lead and arsenic, are used for all lenses and prisms.