Half the weight, half the glass, one eye · review
A zoom monocular running from 10x to 30x on a 40 mm objective, with BAK4 prisms, dual focus and a nitrogen-filled aluminium body.
The bottom line A convenient daytime zoom whose useful range is the bottom half of what is printed on it.
A 40 mm objective divided by 10 gives a 4 mm exit pupil; divided by 30 it gives 1.3 mm. That single calculation describes the whole instrument: perfectly usable at the low end, increasingly difficult at the high one, with everything in between on a sliding scale.
BAK4 prisms, a 20 mm eyepiece lens, an FMC green film with an HD blue film, an aluminium and rubber body with a nitrogen filling, and dual focus. The coating description mixes a standard label with two marketing names; only the first can be compared with anything.
The first bullet states outright that the phone clip and mount are not included. Listings in this family frequently imply otherwise, and saying so plainly is worth a line here.
Set it at 10x or 15x, find the subject, then zoom only if the light allows. That order — find wide, then magnify — is the same discipline a telescope asks for, and it applies here for the same reason.
German Amazon store sat at about 26 € on the day of the survey.
American and British Amazon stores list it in local currency, which the euro range above sets aside.
Spanish Amazon store stood above 1.6× the cheapest country. A gap that size normally means stock forwarded from abroad rather than a seller on the ground, so that figure is left out of the range above.
French and Italian Amazon catalogues hold a record for it that nobody is selling.
Figures as Keepa reported them on the day this page was last updated. Stock and pricing shift without warning.
Prices quoted in this text were read on 17 September 2026. The live price is at the top of the page.
| Aperture | 40 mm |
|---|---|
| Magnification | 10x to 30x, variable |
| Exit pupil | 4 mm at 10x falling to 1.3 mm at 30x |
| True field of view | Not published by the maker. |
| Close focus | Not published by the maker. |
| Prism | BAK4 prisms with FMC green and HD blue films, per the maker |
| Coatings | Not published by the maker. |
| Sealing | Not published by the maker. |
| Weight | Not published by the maker. |
| Phone adapter fit | Not published by the maker. |
| Supplied accessories | Phone clip and mount, stated explicitly by the maker |
| Amazon reference | B07KPRHNM6 (same reference on 6 Amazon marketplaces) |
| EAN | 0755987122824 |
Forty divided by thirty gives a 1.3 mm exit pupil. The image gets dim, the eye position becomes critical, and floaters in the eye become visible. Most zoom monoculars are used near the bottom of their range for good reason.
Optically, always. A zoom has more elements, more surfaces and a design that must work across a range rather than at one point. What it buys is convenience, and that is a real benefit in daylight.
12x · 50 mm · 435 g · waterproof and nitrogen-filled
A 12x50 monocular with BaK-4 glass, UR coating, a twist-up eyecup and a nitrogen-filled waterproof body, published at 435 g.
Best for: A pocket instrument for dusk that is meant to be used in poor weather
≈ $130 / £96 / €79
10–30x zoom · 50 mm objective · supplied with phone holder and tripod
A 10–30x zoom monocular on a 50 mm objective, IPX7-sealed and nitrogen-filled, supplied with a phone holder and a metal tripod.
Best for: Daytime and dusk viewing with a phone, where the tripod does the steadying
≈ £31 / €24
12x · 55 mm · 352 ft at 1000 yd · IPX7
A 12x55 monocular with a 20 mm BAK-4 prism, FMC optics, IPX7 sealing and a supplied smartphone adapter.
Best for: Birdwatching and dusk viewing where the extra five millimetres of objective earn their weight
≈ $109 / £86 / €90
