Yeah I know, monoculars are often considered the Red Headed Stepchild of field optics. I know I felt that way about them for many a year but this thread is an attempt to champion the little bastards... bear with me please.
My frustrations in looking for a very small binocular to carry with me while walking my dog led me to this, so blame can be placed at the feet of compact bin makers. Seriously though, I only like the most expensive pocket bins and really didn't want to pony up what they cost for the limited use they'd see. Lesser bins left me cold and the want of a convenient pocket optics remained, so drum roll, open curtains, queue the lights... I bought a Nikon HG 5x15 Monocular!
My quick appraisal is that it fits the bill. The optics are quite sharp and contrasty, has a 9 degree FOV, easy to focus (turning the eyepiece), and is very light and small. The little Nikon has plenty of eye relief so I can easily see the full FOV with sunglasses on. It weighs a whopping 2 1/2 oz. and hung from it's cord around the neck, or slipped into a shirt pocket, can hardly be noticed.
For my intended use of just getting a quick look at birds in the 'hood and making IDs, it works well. The low 5x power makes holding steady easy and lends a reasonable 3mm exit pupil. The case is made of titanium though it is not rated as waterproof, which I found a bit odd because it's hard to imagine any field optic being easier to make waterproof than a monocular with a screw in eyepiece.
Last, these things aren't cheap. They usually go for about $200. US but Adorama has the 5x versions for $149. I looked at the Zeiss but they're around $300. US for the 6x18 version and I dubbed that being too expensive for this kind of experiment.
Here's a few pics to lend scale and act as eye candy for you optics geeks that don't quite have everything, yet!
I have the same monocular, and I love that I can stick it a pocket, walk anywhere, and use it whenever I feel like it. Wrapping your hand around it makes it disappear. So small, so light, and a beautiful titanium body that is probably rugged as heck, but beautiful enough to look delicate. Great optics (I have the binocular equivalent, too; never mentioned and under-appreciated!).
On the other end of the spectrum, I have the 20x60 Zeiss Monocular with mechanical stabilization. Pretty cool.