The 10x42 Excursion HD Binocular from Bushnell utilizes compact roof prisms and an open-bridge design to create a capable optic that is comfortable to hold and use for prolonged periods. Anti-reflective fully multicoated lens surfaces and reflective PC-3 prism coatings increase the amount of light getting through the optical system. This increased light transmission produces high-contrast images that are bright and clear, with minimal distortion across the entire wide-angle field of view. The housing is nitrogen-filled and o-ring sealed for water and fogproof performance in all weather conditions. A large and lockable center focus wheel is easy to use when it's cold or wet, or when wearing gloves. Textured rubber armor provides a non-slip grip.