Acebeam H40 SST20 headlamp review

Luminus SST20 LED
600 lm output
4104 cd intensity
1 x 14500 Li-Ion or 1 x AA NiMH battery

The Acebeam H40 SST20 headlamp was released in 2019. It uses Luminus SST20 LED, OP reflector and 1 x 14500 Li-Ion or 1 x AA NiMH battery. The powerful emitter in this headlamp provides up to 600 lm output, 4104 cd intensity, and a beam distance of 128 m.

Excited to learn if the H40 SST20 lives up to expectations? Read on!

Table of Contents

  • Acebeam H40 SST20 specifications
    • Body, materials, weight, colors
    • System, LED, lens, reflector
    • Performance, flux, intensity, throw
    • Software, user interface, modes
    • Features, battery, protections
    • Accessories, package contents
  • Conclusion, pros and cons
  • Photos

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. If you found an error or something lacking in the specifications for the Acebeam H40 SST20, then tell us.

Acebeam H40 SST20 / H40SST20

The H40 SST20 is useful when you need to use both hands. You need both hands in camping, hiking, or working in low-light. This light has 3 modes of lighting. The H40 SST20 mode memory eliminates the need to cycle through modes. You don't have to do this each time you turn on the flashlight. It provides convenience and saves time.

Acebeam H40 SST20 specifications

NameH40 SST20
Rated 3 / 5 based on 1436 user votes.

Headlamps have a light attached to a headband. This allows users to wear them without using their hands.

Acebeam H40 SST20 / 1

Body, materials, weight, colors

Weight34 g
Length64.7 mm
Body diameter23.4 mm
Head diameter26.9 mm
Materialaluminium alloy with HAIII hard-anodized finish

The H40 SST20 is small, compact, and designed for ultra-portability. A smaller flashlight is easier to carry in a pocket, bag, or pouch. This makes it more convenient for everyday use or when you're on the go. The aluminium body of the H40 SST20 has excellent thermal conductivity. This means it can effectively dissipate heat generated by the flashlight's components. The body of H40 SST20 flashlight treated with a Type III hard-anodized, anti-abrasive finish. The H40 SST20 flashlight comes in a stylish black color.

Acebeam H40 SST20 / 2

System, LED, lens, reflector

EmitterLuminus SST20 LED
Color temperature4000 K
Lenstoughtened AR coated glass
Switchelectronic side

Luminus has established a positive reputation as a reliable LED manufacturer. Warm, white light is generally more comfortable. It's also less harsh on the eyes than cool, white light. The designers of the H40 SST20 incorporated an orange peel reflector to enhance the beam. It does this by diffusing the light from the light source. The AR coating reduces the loss of light due to reflections, allowing more light to pass through the lens. The electronic switches may have a higher chance of standby drain.

Performance, flux, intensity, throw

Flux600 lm
Intensity4104 cd
Throw128 m
CD/LM factor6.84

600 lm can provide a decent amount of brightness and be suitable for many everyday tasks. The H40 SST20 flashlight has 4104 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. Candela per lumen (cd/lm) measures a flashlight's beam intensity. It compares this to its total luminous flux or output. If accurate color is a priority for you, choose a flashlight with a CRI of 90 or above. The H40 SST20 flashlight has a CRI of 95. It offers the best color representation, colors can be seen as intended.

Software, user interface, modes

Modes3 modes
Mode memoryyes
Ramping modeyes

A flashlight's modes are different output settings or brightness levels. They can be chosen to meet different needs and preferences. The flashlight has mode memory. It remembers the mode you were using when the light was last turned off. It stays in that mode when you turn it on again. The ramping mode has an advantage. It offers precise control over the light amount emitted by the flashlight. The SOS flashes Morse code so you can signal for help when needed.

Features, battery, protections

Battery1 x 14500 Li-Ion or 1 x AA NiMH battery
Battery indicatorno
Charger portno
Thermal regulationno

The H40 SST20 flashlight's power source is 1 x 14500 Li-Ion or 1 x AA NiMH battery. It provides reliable, long-lasting energy for top performance. The H40 SST20 cannot charge batteries. You may need an external charger to keep your battery going. The flashlight detects when the battery's voltage has dropped to a certain level. Then, it reduces or cuts off the power. Flashlights without thermal protection may rely on other design elements to dissipate heat. These elements include heat sinks, fins, or body materials with good thermal conductivity.

The "6" in the IP68 rating shows the level of protection. It's against solid objects, like dust and foreign particles. The "8" in the IP68 rating means the highest level of protection. It is against water ingress.

Accessories, package contents

Package contents2 x spare o-rings

When using spare O-rings, follow the maker's instructions. Use their guidelines for proper installation.

According to the ANSI/NEMA FL1 Standard, we measure the performance of the H40 SST20 flashlight 30 seconds after switching on the light. The ANSI/NEMA FL1 2009 Standard is a set of flashlight performance guidelines.

Conclusion, pros and cons

This Acebeam 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
  • OP reflector
  • AR coated lens
  • side switch
  • superior CRI
  • multiple modes
  • mode memory
  • ramping mode
  • SOS/beacon function
  • low-voltage protection
  • dust protected
  • waterproof


  • moderated performance
  • low intensity
  • no battery indicator
  • no built-in charger
  • no thermal regulation
  • no auxiliary LEDs
  • non-magnetic


Acebeam H40 SST20 / H40SST20 photo 1.
Acebeam H40 SST20 / H40SST20 photo 2.
Acebeam H40 SST20 / H40SST20 photo 3.
Acebeam H40 SST20 / H40SST20

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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.
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