Vortex Optics 2012 Crossfire Binoculars 10x42 Fully multi-coated optics brighten every view. Powered for all-around viewing. High-density BaK-4 glass elements deliver sharper, more detailed images. Tightly sealed binocular keeps out water. Waterproofing with O-ring seals keeps water on the surface of the binocular and away from the optics.