Sofirn/Headlamp

Sofirn SP40A

Name: Sofirn SP40A
Brand: Sofirn
Price: 25 USD
Availability: InStock

Budget right-angle headlamp with magnetic tailcap. The SP40 works great as both a headlamp and a magnetic work light. Solid CRI and USB-C at a great price.

Beam profile

Flood, about 33° wide. Wide and even — light where you are, not where you're pointing.

Estimated from 1,200 lm ÷ 4,620 cd — how this works

$25

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Specifications

Output: 1200lm
Peak intensity: 4620cd
Beam distance: 136m
Emitter: LH351D 5000K
Colour rendering: 90 CRI
Beam type: Flood
Cell: 18650
Runtime: 2 hrs (high)
Modes: 4 Stepped
Interface: Simple
Water/dust: IPX7
Dimensions: 4.25 x 1.0 in
Weight: 2.2 oz
Warranty: 1 Year

Manufacturer figures, measured to ANSI FL1 where the brand states it.

Features

High CRI (90+)USB-C Charging Waterproof (IP67+)

What owners report

Sofirn SP40A/5 sources reviewed

The SP40 was, for several years, the default answer to "cheapest headlamp worth owning". An 18650 right-angle light with a magnetic base, aircraft-grade aluminium and machining reviewers describe as very high quality, at a price that undercut everything comparable.

The compromises are of its era. Charging is micro-USB rather than USB-C, and there's no strobe or SOS — an omission some owners actively prefer. Output is completely unregulated, tracking down with cell voltage, though in practice it only sheds about 10% in the first hour, which nobody notices. The magnetic base is the feature owners single out: pull it off the headband and it's a work light that sticks to anything steel.

Consistently praised

Magnetic base turns it into a stick-anywhere work light off the headband
Aircraft-grade aluminium with machining quality well beyond the price
Four genuinely useful brightness levels, with a very bright 1,200 lumen turbo
Headband comfort improved over earlier Sofirn models
Long-standing reputation as the best-value 18650 headlamp with onboard charging

Common complaints

Micro-USB charging rather than USB-C — the clearest sign of its age
Output is unregulated and tracks the cell voltage down
No strobe or SOS mode at all
The head strap is thinner than premium brands'
Superseded by newer Sofirn headlamps with USB-C and better emitters

Questions people ask

Is the SP40 still worth buying?: Only if it's very cheap. Newer Sofirn headlamps offer USB-C and better emitters for similar money. The SP40's build quality and magnetic base remain good, but micro-USB is a real inconvenience now.
What does 'unregulated output' mean here?: Brightness gradually falls as the cell drains rather than holding a set level. Measured, it's about a 10% drop in the first hour, which is below what the eye notices — so it matters less than it sounds.
Can it be used off the headband?: That's arguably its best feature. The magnetic tail sticks to any steel surface, so it works as an under-bonnet or workbench light without the strap.
What's the difference between the SP40 and the SP40A?: The SP40A is the AA-compatible variant. It's dimmer and shorter-running, but takes a cell you can buy anywhere, which suits an emergency or travel light.

Sources (5)