A good article for beginners so they understand what the folks on the forum are talking about.
Wingspan Optics, like a number of brands you find in the USA isn't generally available in the UK, Amazon will import their binoculars but not their monoculars.
Its years since I have seen anyone actually use a monocular in public.
Years ago I had a pair of miniature binoculars, that vaguely resembled a very thick credit card when telescoped down for travel. I personally couldn't get them close enough to my eyes to get a good steady view from them, but they were even more pocketable than many monoculars. About the only very small viewing devices I ever found anywhere near practical were the miniature binoculars produced by various people including Nikon some time ago.
Personally, for the casual user, Nikon's range of reverse porros have always been affordable, compact and generally acceptable optically. I have a 7x somewhere that is many decades old and still going strong.