Black Diamond Optics Gen 2 10x42mm High Definition ED BAK4 Roof Prism Binoculars Black. The waterproof housing gas-filled with nitrogen ensures superior clarity in any condition. A large focus wheel allows for quick and accurate focus. Adjustable eye relief and a rubberized housing round out these quality binoculars that are great for field stand or bird watching. Specifications for Black Diamond Optics Gen 2 10x42mm High Definition ED BAK4 Roof Prism Binoculars: Manufacturer: Black Diamond Optics Color: Black Magnification: 10 x Objective Lens Diameter: 42 mm Prism System: Roof Prism Material: BAK4 Eye Relief: 0.768 in Exit Pupil: 0.165 in Field of View Angle: 6 degrees Binoculars Focus System: Center Focus Close Focus: 9 ft Water Resistance Level: Waterproof Length: 5.4 in Weight: 24.69 oz Fabric/Material: Aluminum Features of Black Diamond Optics Gen 2 10x42mm High Definition ED BAK4 Roof Prism Binoculars High Definition ED glass Light Weight construction BAK4 Prism w/ Dielectric Coating Nitrogen filled Large focus wheel Adjustable eye piece and rubberized housing Package Contents: Black Diamond Optics Gen 2 10x42mm High Definition ED BAK4 Roof Prism Binoculars Case and lens covers Neck strap Cleaning cloth Owners manual. Black Diamond Optics 10x42ED: Gen 2 10x42mm High Definition ED BAK4 Roof Prism Binoculars Black