I always thought that a monocular was one of those little round pieces of glass that evil villains wear in one eye. Turns out that's not it: the correct answer is monocle. Monocle. After getting over my initial disappointment that Brunton had not sent me some good villain kit, I discovered that the Eterna 4070W 6×30 monocular is nonetheless a great piece of gear.
The nitrogen-filled Eterna is water- and fog-proof, weighs only 10oz with caps and leash, and is compact at 6in long by 2in diameter. It's not the smallest monocular Brunton makes, but the tradeoff is an armored body with a grippy rubber rand that makes it easy to hold and point with gloves on. It's easier to maneuver and stow than a pair of binos, making it much faster to get into action.
The optics are very nice, fully coated with a sharp 341ft field of view at 1,000 yards. The 30mm objective outperforms its size, offering superb low light performance. A generous 19mm of eye relief means no mashing your eyeball against the lens. Overall the 6x magnification is great for mountaineering use such as scoping out routes, observing other climbers and other useful tasks. If you want a long looker for dedicated trail use, check out the Eterna.