The Bushnell H2O 7x 50 mm Binocular presents a large 50 mm objective to deliver lots of light transmission for low-light conditions that makes this Porro binocular a perfect choice for the twilight of dusk and dawn. It also bes an important feature during overcast weather. O-ring sealed and nitrogen purged with a unique micro-ridged rubber armor covering that hinders slippery holds when wet. This binocular was made for H2O viewing situations. The optics is excellent, boasting BAK4 prisms and multi-coatings that pass through bright, clear, high contrasted images. Twist-up eyecups allow comfortable viewing for those with or without eye or sunglasses. The large center focusing knob makes focusing easy and quickly accessible even when wet.