Years ago, I got fed up with carrying heavy binos around my neck all day. Decided I wanted a light weight roof prism binocular. I went to K-Mart, tried the Bushnell and Simmons, returned both of them. Mostly they would not maintain focus with bouncing around. Then I bit the bullet and bought a Leitz Trinovid 10x 20mm bino. I have had it ten years now, and never a problem. Only drawback is that the small objective reduces light reception early morning and late evening, as opposed to larger Objectives. I believe they can be purchased for around $350.