Astrolux S43S LH351D flashlight review

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

The Astrolux S43S LH351D flashlight was released in 2020. 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.

Curious if this Astrolux flashlight is a real gem? Keep following along!

Table of Contents

  • Astrolux S43S 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 S43S LH351D / S43SLH351D

The S43S LH351D flashlight is an essential tools for emergency preparedness. TIR technology minimizes hotspots, dark spots, and irregularities in the beam of S43S LH351D. The memory function is a nice feature, the light will remember the last used mode. It has a strobe function, which is one of the most effective self defense tools available. This USB rechargeable flashlight eliminates the need for disposable batteries.

Astrolux S43S LH351D specifications

NameS43S LH351D
Rated 3 / 5 based on 1521 user votes.

The S43S LH351D flashlight allows you to light dark areas.

Astrolux S43S LH351D / 6

Body, materials, weight, colors

Weight60 g
Length88.7 mm
Head diameter27 mm
Materialcopper head, aluminium alloy body with HAIII hard-anodized finish

The S43S LH351D is small, compact, and designed for ultra-portability. The length of a flashlight can affect how it feels in your hand and how you can grip it. The aluminium body of the S43S LH351D has a reputation for being durable and strong. The HAIII coating is uniform and attractive. The S43S LH351D flashlight comes in a stylish black color.

Astrolux S43S LH351D / 7

System, LED, lens, reflector

Emitter4 x Samsung LH351D LEDs
Color temperature5000 K
Switchelectronic side

Samsung has invested a lot in research and development. Color temperature is used to quantify the color appearance of light sources. The TIR lens of the S43S LH351D can reduce light loss, it captures and redirects much of the emitted light. The flashlight has electronic switches.

Astrolux S43S LH351D / 2

Performance, flux, intensity, throw

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

The S43S LH351D flashlight has 4000 lm. It will provide an exceptionally bright and powerful beam of light. The S43S LH351D flashlight has 8464 cd, it provides a much brighter and more intense beam. The throw is the distance in meters at which the flashlight produces a light intensity of 0.25 lux. 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 S43S LH351D flashlight has a CRI of 95, it offers the best color representation.

Astrolux S43S LH351D / 4

Software, user interface, modes

Mode memoryyes
Ramping modeyes

NarsilM has a user-friendly interface. It allows for intuitive operation and navigation through modes and settings. The flashlight has mode memory. It remembers the mode you were using when the light was last turned off. The S43S LH351D's ramping mode is easy to use. It lets you smoothly change the output over its whole range. You can use Strobe for signaling purposes. It can also be used for self-defense or to attract attention in emergency situations. The S43S LH351D's SOS mode produces a specific sequence of long and short flashes.

Astrolux S43S LH351D / 3

Features, battery, protections

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

The Astrolux S43S LH351D flashlight is powered by 1 x 18650 Li-Ion battery. The battery indicator helps users check the battery status. The built-in charger allows for convenient and versatile charging. The flashlight detects when the battery's voltage has dropped to a certain level. The built-in thermal control adjusts brightness output to prevent overheating. The IPx6 rating indicates that the flashlight has a protection against water jets.

Astrolux S43S LH351D / 5

Accessories, package contents

Package contents18350 tube
spare o-ring
survival hammer

The clip is useful to keep the light secured in your pocket. Securing the flashlight with a lanyard frees up your hands for other tasks. Replacing worn or damaged O-rings helps a lot.

Astrolux S43S LH351D / 1
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 S43S LH351D / S43SLH351D photo 1.
Astrolux S43S LH351D / S43SLH351D photo 2.
Astrolux S43S LH351D / S43SLH351D photo 3.
Astrolux S43S LH351D / S43SLH351D photo 4.
Astrolux S43S LH351D / S43SLH351D photo 5.
Astrolux S43S LH351D / S43SLH351D photo 6.
Astrolux S43S LH351D / S43SLH351D photo 7.
Astrolux S43S LH351D / S43SLH351D photo 8.
Astrolux S43S LH351D / S43SLH351D


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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.