BAK4 Porro Prism Fully Multicoated Optics Angle of View: 44° Nitrogen-Filled, Water and Fogproof Closed Bridge Configuration Large Center Focus Wheel Tripod Mountable with Optional Adapter Fold-Down Rubber Eyecups Designed for both astronomical and terrestrial use, Pentax's 20x60 S-Series SP WP Binoculars can be used with confidence in all weather and conditions. The large oversized 60mm objectives are fully multicoated to reduce reflection and maximize light transmission through the entire optical path. Utilizing the traditional porro prism configuration gives