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Ferrex FS-ARM 4037 review

A 37 cm brushless machine with six central height steps, a 40-litre box with a level indicator and a folding handle.

The bottom line Sits between the small machines and the wide ones: 37 cm, six central steps across the full 25 to 75 mm, and a 40-litre box with a level indicator. The maker recommends it up to 250 m², which is the most conservative stated area on this shelf and probably the most honest.

What the maker prints on its own page

A cordless mower on a 40 V platform with a brushless motor, recommended for lawns up to 250 m². The cutting width is 37 cm and the height adjusts centrally in six steps between 25 and 75 mm. The grass box holds 40 litres and carries a level indicator. The handle is an ergonomic soft grip, adjustable for height and folding for storage, and a carrying handle is integrated.

The middle of the shelf, and the full range

37 cm sits between the 30 to 33 cm machines and the 42 to 43 cm ones. What it has that several of the wider machines do not is the complete height range — 25 to 75 mm — in six central steps.

That is worth more than it looks. The cutting height is the one variable on this whole site that costs nothing and changes everything, and a machine restricted to a narrow band is a machine that cannot be raised in a drought or dropped in spring.

The 250 m²

The most conservative stated area in the family. Every one of these figures is the maker’s own arithmetic on conditions it does not publish, and a low one is a better sign than a high one — it suggests the assumption was closer to a real lawn.

The gap this listing leaves

Nothing states whether a pack and a charger are in the box, and no pack capacity is given. On a cordless machine those are the two figures that determine both the real price and how long it runs, and this page records their absence rather than guessing at either.

Availability

No offer stood anywhere on the day of the survey — six stores asked, six blanks.

Listed and unsold: the German, American, British, French, Italian and Spanish Amazon catalogues hold the reference with nobody behind it.

Taken from Keepa on the day this page was last revised; stock and prices move without notice.

The declared figures, and the point they stop at

Strengths

  • The full 25 to 75 mm range in six central steps, which several wider machines here do not offer
  • A 40-litre box with a level indicator on a 37 cm deck
  • A folding handle and an integrated carrying handle, both stated

Compromises

  • The listing does not state whether a pack and charger are included
  • No pack capacity, so the energy on board cannot be worked out
  • No weight, no noise figure, no price read on any of the six markets at the time of survey

Specifications

Cutting width37 cm, as stated
Battery platform40 V, brushless motor as stated
Battery suppliedNowhere in this listing
Stated areaUp to 250 m², as stated by the maker
Cutting heights25–75 mm, central adjustment in 6 steps
Catcher volume40 L, with a level indicator
FunctionsNot published — no count given
Guaranteed noiseNot published
WeightNot published
Amazon referenceB0H4Z59J27 (one reference across 6 Amazon marketplaces)
EAN0688116573009

What this machine usually gets asked

Is a pack in the carton?

The listing does not say, and this page does not assume. On a cordless shelf that is the single most consequential omission there is: the same machine as a bare tool and as a complete kit are two different purchases at two different real prices.

Is 250 m² pessimistic?

It is the most conservative figure on this shelf, and a conservative assumption is a better sign than a generous one. All of these numbers are manufacturers’ arithmetic on conditions they do not publish.

Why does the height range matter more than the number of steps?

Because the range says what the machine can do and the step count says how finely. A machine with seven steps between 35 and 65 mm cannot cut at 25 mm at all, and several listings here give the count without the range.

Who this one is for

A small to medium lawn, for a buyer who will confirm the carton contents before ordering

Price and availability

A reference exists on these Amazon stores: France, Germany, Italy, Spain, United Kingdom, United States. Listed is not the same as in stock — availability changes daily.

Details checked on September 26, 2026.

Sources

Specifications: manufacturer sheet and Amazon product page. Prices and availability: Keepa. No product on this site has been physically tested.

How we assess products