The 7x50 h20 porro binocular from bushnell delivers a fogproof housing and rubber armoring textured with soft ridges to keep grip this porro prism binocular offers less light loss and greater depth of field than comparable roof prism designs a multicoated lens system and high transmission bak4 prism glass allow these weather sealed glasses display clear and bright images that are crisp with every spec of detail bak4 porro prisms multicoated optics nitrogen filled fogproof water