Nikon 7561 42mm 8x42 EDG Binocular Features Nikkor lenses to help eliminate chromatic aberration Includes a dual-phase central focusing knob for precise focusing and diopter adjustments Incorporates phase-correction coated roof prisms to enhance resolution Designed for ergonomic functionality, durability and precise balance in the hand Offers thumb-indexing contours to the underside of the 42mm body