Brunton Echo 10x42 Full Size Waterproof Binoculars Our newest binocular line changes the face of sporting optics for good. An entry-level binocular that impresses the experienced, the Echo delivers features never before imagined on a sporting binocular. Echo Full Size is built around Bak-4 prism glass with our famous Emerald Fire™ full multi-coatings. We’ve given the Echo line our new twist-up eye relief system for eyeglass compatibility and more comfortable viewing. Waterproof and nitrogen filled, these binoculars are backed by an incredible 5-year warranty offering you peace of mind for your investment.