Astrolux S43 LH351D flashlight review

4 x Samsung LH351D LEDs
4000 lm output
8464 cd intensity
1 x 18650 Li-Ion battery

The Astrolux S43 LH351D flashlight was released in 2018. It uses 4 x Samsung LH351D LEDs, TIR reflector and 1 x 18650 Li-Ion battery. The powerful emitter in this flashlight provides up to 4000 lm output, 8464 cd intensity, and a beam distance of 184 m.

Wondering if this Astrolux flashlight is a must-have? Keep reading to find out!

Table of Contents

  • Astrolux S43 LH351D specifications
    • Body, materials, weight, colors
    • System, LED, lens, reflector
    • Performance, flux, intensity, throw
    • Software, user interface, modes
    • Features, battery, protections
    • Accessories, package contents
    • Links
  • Conclusion, pros and cons
  • Photos
  • Comparisons

The content of this article reflects our own experiences and viewpoints. We aim to offer insights on a topic, and we hope others find it helpful and motivating. Additionally, we make every effort to provide accurate and comprehensive coverage.

Astrolux S43 LH351D / S43LH351D

The S43 LH351D is a powerful and reliable flashlight. It has impressive illumination and durable construction. TIR lens plays a significant role in shaping the beam pattern of the S43 LH351D flashlight. The S43 LH351D's mode memory makes the user experience more seamless and intuitive. It has a strobe function, which is one of the most effective self defense tools available. This USB rechargeable flashlight has become popular.

Astrolux S43 LH351D specifications

NameS43 LH351D
Rated 4 / 5 based on 1518 user votes.

The S43 LH351D flashlight enhances safety.

Astrolux S43 LH351D / 1

Body, materials, weight, colors

Weight60 g
Length88.7 mm
Head diameter27 mm
Materialaluminium alloy body with HAIII hard-anodized finish

An extremely lightweight handheld flashlight weighs 60 g. Consider the length of the flashlight, it should fit comfortably in your chosen way to carry it. The aluminium body of the S43 LH351D has a reputation for being durable and strong. The body of S43 LH351D flashlight treated with a Type III hard-anodized, anti-abrasive finish. This flashlight comes in a sleek black color option.

Astrolux S43 LH351D / 6

System, LED, lens, reflector

Emitter4 x Samsung LH351D LEDs
Color temperature5000 K
Switchelectronic side

The emitter of S43 LH351D manufactured by Samsung, a Korean LED manufacturer. Color temperature is used to quantify the color appearance of light sources. The S43 LH351D's TIR lens is made of a single piece of transparent material. The flashlight has electronic switches.

Astrolux S43 LH351D / 7

Performance, flux, intensity, throw

Flux4000 lm
Intensity8464 cd
Throw184 m
CD/LM factor2.12

The S43 LH351D flashlight has 4000 lm. It will provide an exceptionally bright and powerful beam of light. The S43 LH351D flashlight has 8464 cd, it provides a much brighter and more intense beam. The throw distance is the farthest distance the flashlight can light an object. The cd/lm factor is the candela-to-lumen ratio. It shows how concentrated a light source's output is. A flashlight with a higher CRI can show colors more accurately. The flashlight has a CRI of 95. It can show colors with exceptional accuracy.

Astrolux S43 LH351D / 4

Software, user interface, modes

Mode memoryyes
Ramping modeyes

NarsilM is an open-source firmware designed for flashlights, it is similar to Anduril. The flashlight has mode memory. It remembers the mode you were using when the light was last turned off. The S43 LH351D's ramping mode is easy to use. It lets you smoothly change the output over its whole range. The S43 LH351D is tactical strobe ready. The strobe light is disorienting to the person it is aimed at, this makes it hard for them to concentrate. The SOS signal is an international distress call.

Astrolux S43 LH351D / 2

Features, battery, protections

Battery1 x 18650 Li-Ion battery
Battery indicatoryes
Charger portmicroUSB
Thermal regulationyes

The Astrolux S43 LH351D flashlight is powered by 1 x 18650 Li-Ion battery. The battery indicator lets you know when the battery is low, charging, or fully charged. This flashlight can charge the battery with a built-in charger. LVP (Low Voltage Protection) is designed to protect the battery. The thermal protection feature helps prevent overheating. The IPx6 rating indicates that the flashlight has a protection against water jets.

Astrolux S43 LH351D / 3

Accessories, package contents

Package contents18350 tube
spare o-ring
survival hammer

With a clip, you can fasten the flashlight to a reachable spot. The lanyard prevents accidental loss of the flashlight. Replacing worn or damaged O-rings helps a lot.

Astrolux S43 LH351D / 5
Official sitehttps://flashlight.nitecore.com/

Conclusion, pros and cons

This Astrolux flashlight, like any other, has its strengths and weaknesses. Let's take a close look at both sides to understand this flashlight better. I share my thoughts on its standout features and the parts that might need improvement. Keep in mind, these are just my opinions, and you might have a different perspective.


  • lightweight
  • aluminium body
  • warm light
  • TIR lens
  • side switch
  • strong flux
  • superior CRI
  • NarsilM firmware
  • mode memory
  • ramping mode
  • tactical strobe
  • SOS/beacon function
  • battery indicator
  • USB charger
  • low-voltage protection
  • thermal regulation
  • waterproof
  • clip


  • no auxiliary LEDs
  • non-magnetic


Astrolux S43 LH351D / S43LH351D photo 1.
Astrolux S43 LH351D / S43LH351D photo 2.
Astrolux S43 LH351D / S43LH351D photo 3.
Astrolux S43 LH351D / S43LH351D photo 4.
Astrolux S43 LH351D / S43LH351D photo 5.
Astrolux S43 LH351D / S43LH351D photo 6.
Astrolux S43 LH351D / S43LH351D photo 7.
Astrolux S43 LH351D / S43LH351D photo 8.
Astrolux S43 LH351D / S43LH351D


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Updated: April 23, 2024

David Hagon
I love bushcraft and flashlights. I find joy in mastering wilderness survival skills and exploring the realm of illuminating gadgets. Bushcraft isn't just fun, it's a learning journey. I form a strong bond with nature. It's more than a hobby, it enriches me in practical and spiritual ways.