I will chime in,, I have spent some time looking through them with the 50 power eye pieces, i believe they also make 30 power,, We spent 7 days glassing big horn sheep in southern ca. They are by far the best giant chunk of glass i have ever looked through, We had 2 swaro spotters to compare to, before the heat thermals moved in we field judged many rams at 2 and 3 miles away. Its not only the 50 power but the massive field of view, plus no eye strain with both eyes opened compared to a single eye of a spotter. The thing is giant, it takes a good tri pod to hold it up, but for all day glassing it would be my 1st choice, To big to carry over the next ridge, get a swaro 65 for that. If you got the bucks go for it !!!!