It multiplies the focal length, and the eye relief survives · review
A 2x achromatic Barlow lens in a full metal body, fully coated, described in four words per bullet.
The bottom line A basic achromatic Barlow behind a listing too short to state its barrel size.
It multiplies the telescope’s effective focal length, so every eyepiece behind it doubles its magnification. Two eyepieces plus a Barlow give four magnifications, and — crucially — the long eyepiece keeps its comfortable eye relief while delivering the short one’s power.
A Barlow sits in a converging beam and can introduce colour error of its own. An achromatic design — two elements — corrects most of it. The maker states the design without stating the element count, which is the usual level of disclosure.
Barrel size. Everything else about a Barlow is secondary to whether it fits the focuser, and this advertisement never says. Four bullets of two words each is the entire description.
“Fully coated” means one layer on every air-to-glass surface — the second rung of the four. The Bresser Barlow on this shelf claims full multi-coating on four elements, which is a different level of specification.
German, French, Italian and Spanish Amazon stores ran from 18 € to 25 € on the day of the survey.
British Amazon store lists it in local currency, which the euro range above sets aside.
American Amazon store gave no result whatever, so the buy button there opens a search rather than an empty page.
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.
| Amplification factor | 2x — it doubles the effective focal length |
|---|---|
| Element count | Achromatic · The listing does not carry it |
| Barrel size | The listing does not carry it |
| Camera thread | Not published by the maker. |
| Effect on eye relief | Not published by the maker. |
| Coatings | Fully coated, as the maker words it |
| Body | Full metal |
| Weight | Not published by the maker. |
| Amazon reference | B006631Z4A (same reference on 5 Amazon marketplaces) |
| EAN | 4250403200149 |
It preserves it. A 10 mm eyepiece with a 2x Barlow gives the same magnification as a 5 mm eyepiece while keeping the 10 mm’s comfortable eye relief — which is the main reason experienced observers own one.
The listing does not say. Barlows in this price class are almost always 1.25 in, and the figure should be confirmed before buying — this page will not supply a number the maker did not print.
0.5x focal reducer · 1.25 in · sold under the name “Barlow”
A 0.5x focal reducer in an anodised aluminium 1.25 in barrel, sold under the name “Barlow lens” while its own description correctly calls it a reducer.
Best for: Widening the field on a long-focal-length telescope, or shortening exposures on a camera
≈ €13
2x Barlow · four elements · fully coated · 80 g
A 2x Barlow with a four-element fully coated design in a 1.25 in barrel, published with its dimensions and weight.
Best for: A Barlow that will be used for photography as well as visually
≈ £35 / €31
114 mm mirror · 900 mm focal length · alt-azimuth mount
A 114/900 Newtonian on a simple alt-azimuth mount, supplied with three eyepieces, a 6x30 finder and a 1.5x erecting lens, recommended by the maker from age eight.
Best for: A family telescope where nobody wants to learn polar alignment
≈ £150 / €142
