Fenix SD20 diving light review

1 x Cree XM-L2 LED, 1x Cree XQE RED LED
1000 lm output
7400 cd intensity
2 x 18650 Li-Ion batteries

The Fenix SD20 diving light was released in 2017. It uses 1 x Cree XM-L2 LED, 1x Cree XQE RED LED, SMO reflector and 2 x 18650 Li-Ion batteries. The powerful emitter in this diving light provides up to 1000 lm output, 7400 cd intensity, and a beam distance of 172 m.

Curious to know if this Fenix diving light is top-notch? Stay tuned for the answer!

Table of Contents

  • Fenix SD20 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 Fenix SD20, then tell us.

Fenix SD20 / SD20

This light has 2 modes of lighting. Without mode memory, this flashlight always starts in the default mode.

Fenix SD20 specifications

Rated 4 / 5 based on 1447 user votes.
Formdiving light

Body, materials, weight, colors

Weight245 g
Length208 mm
Body diameter26 mm
Head diameter40 mm
Materialaluminium alloy with HAIII hard-anodized finish

The heavier flashlight may be tiring to hold for a long time. It may also be unsuitable for activities that need light weight. The best flashlight size depends on personal preference. It also depends on intended use and the specific features you want. The aluminum bodies can be anodized. This adds a protective layer and a wide range of color options for flashlight bodies. Flashlight makers widely use HAIII coating. It is durable, resists corrosion, and improves grip. It also looks good. This flashlight features a captivating black color.

System, LED, lens, reflector

Emitter1 x Cree XM-L2 LED, 1x Cree XQE RED LED
Color temperature6500 K
Lenstoughtened AR coated glass
Switchrotary front

Cree is widely regarded as a reputable LED manufacturer. Warm, white light is generally more comfortable. It's also less harsh on the eyes than cool, white light. If you need long-range light, get a flashlight with a smooth reflector. It will have more throw distance. The AR coating on the lens maximizes light transmission. This makes the flashlight more effective in darker environments.

Performance, flux, intensity, throw

Flux1000 lm
Intensity7400 cd
Throw172 m
CD/LM factor7.4

The 1000 lm output of SD20 provides great flexibility. You can adjust the brightness to fit different needs. The SD20 flashlight has 7400 cd. It provides a much brighter and more intense beam. The throw distance is the farthest distance the flashlight can light an object. Candela per lumen (cd/lm) measures a flashlight's beam intensity. It compares this to its total luminous flux or output.

Software, user interface, modes

Modes2 modes
Mode memoryno
Ramping modeno

A flashlight's modes are different output settings or brightness levels. They can be chosen to meet different needs and preferences.

Features, battery, protections

Battery2 x 18650 Li-Ion batteries
Battery indicatoryes
Charger portno
Thermal regulationyes
Protectiondepth 100 meters
Specialsred light
white light

The SD20 flashlight's power source is 2 x 18650 Li-Ion batteries. It provides reliable, long-lasting energy for top performance. The battery indicator prevents surprise power failures. It ensures the flashlight is ready when needed. The SD20 doesn't have charger port. The Low Voltage Protection helps save the battery's capacity. It stops it from reaching a critically low voltage. The thermal protection feature helps prevent overheating. Overheating can harm the flashlight's performance, battery, and safety.

Accessories, package contents

Package contentsconducting plate
spare o-ring

The lanyard of the SD20 protects the flashlight from accidental damage. It does this by stopping it from falling or hitting the ground. 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 SD20 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 Fenix 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
  • AR coated lens
  • rotary switch
  • adequate performance
  • multiple modes
  • battery indicator
  • low-voltage protection
  • thermal regulation


  • cool light
  • no mode memory
  • no built-in charger
  • no auxiliary LEDs
  • non-magnetic


Fenix SD20 / SD20 photo 1.
Fenix SD20 / SD20

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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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