Fenix SD20 Diving Light – DISCONTINUED

Max Lumens: 1000
Modes: 3
Battery: 18650 or CR123A
(4 customer reviews)


Out of stock

Fenix SD20 diving light is specifically designed with the diver in mind. A maximum 1000 lumens, 564ft (172m) of beam distance, and waterproof up to 100 meters, allows you to explore the depths with confidence and safety. Easily choose between the different modes with one hand via the rotating magnetic ring on the head of the flashlight. Always know your flashlight’s remaining battery life with the built-in indicator and never lose your light with the bigger button hook and premium included lanyard.

EAN: 6942870303840
Categories: ,
For commercial orders and large purchases, contact us at (888) 775-9996 x6, or
WARNING. Be aware of counterfeit Fenix merchandise in the U.S. marketplace.

Max Lumens: 1000
Modes: 3


fenix sd20 flashlight specs

Flashlight Size:

Length: 8.2” (208mm)
Diameter: 1.0” (26mm)
Head: 1.6” (40mm)

Flashlight Weight:

8.6 oz. (245g) excluding batteries


Two 18650 rechargeable Li-ion batteries or four CR123A Lithium batteries


Lanyard, spare O-ring, conducting plate* (*Taken between the batteries with flat top.)


Limited Lifetime Guarantee from Fenix Lighting US

Additional Features of the Fenix SD20

  • Uses Cree XM-L2 U2 and Cree XQE Red LED with a lifespan of 50,000 hours
  • Rotating magnetic ring for one-hand control
  • Double-layer body tube guards against corrosion
  • Integrated white and red light illumination
  • Digitally regulated output maintains constant output
  • Intelligent over-heat protection to avoid high temperature of the surface
  • Low-voltage warning reminds when battery replacement is needed
  • Reverse polarity protection, to protect from improper battery installation
  • Tail cap with big buckle for fast and convenient quick draw
  • Made of durable aircraft-grade aluminum
  • Premium type III hard-anodized anti-abrasive finish
  • Toughened ultra-clear glass lens with anti-reflective coating

Operation Instruction

Rotate the magnetic ring to select the wanted output level.

From left to right, there are five output levels: Battery level, Red light, Off, Low and High.

Battery Level Indicator

When rotating the magnetic ring to the battery level output, there are three states: red light constant-on displays sufficient power level, red light slow flash displays poor battery level, red light quick flash displays critical battery level.

Low-voltage Protection

  1. When the light works at High output, if the detected voltage is lower than the preset voltage of 6.2V, the output will automatically downshift to 400 Lumens.
  2. When the light works at High or Low output, if the detected voltage is lower than the preset voltage of 6.0V, the output will automatically downshift to 100 Lumens.
  3. When the light works at the Red light mode, if the detected voltage is lower than the preset voltage of 6.0V, the output will automatically downshift to 25 Lumens.

Intelligent Over-heat Protection

The light will accumulate a lot of heat when it is working at High output. When the light is overheated internally up to 65 ℃ or above, the flashlight will automatically adjust the output to prevent the light from overheating.

Battery Replacement

Unscrew the tail cap to insert the battery with the anode side (+) towards the light head, and then screw the tail cap.

Usage and Maintenance

  • Disassembling the sealed head can cause damage to the light and will void the warranty.
  • Fenix recommends using excellent quality batteries. If the lamp will not be used for an extended period, remove the battery, or the lamp could be damaged by electrolyte leakage or battery explosion.
  • Long-term use can result in O-ring wear. To maintain a proper water seal, replace the ring with an approved spare.
  • Periodic cleaning of the battery contacts improves the lamp’s performance as dirty contacts may cause the lamp to flicker, shine intermittently or even fail to illuminate for the following reasons:

Reason A: The batteries need replacing.
Solution: Replace batteries (Please confirm the correct installation of anode and cathode).

Reason B: The threads, PCB board contact or other contacts are dirty.
Solution: Clean the contact points with a cotton swab soaked in rubbing alcohol.

If the above methods don’t work, please refer to the warranty policy before contacting your authorized distributor.

SD20 and SD11 Dive Light
SD20 in Hawaii

4 reviews for Fenix SD20 Diving Light – DISCONTINUED

Based on 4 reviews
5 star
4 star
3 star
2 star
1 star
  1. Brad

    Outstanding dive light! Have used it over 20 dives both day and night. Light weight, very bright, long run time and easy to handle. Holding up great to the salt water

    (0) (0)
  2. Jared Romans (verified owner)

    I’ve used my fenix sd20 for 3+ years now as my primary dive light. Double o ring seal, magnetic selection ring, dual leds with DUAL reflectors. It really throws out the brightness. I came to buy one for my new dive buddy. What happend to the sd10? I run it for my backup just cause your supposed to have one. The smaller size a only needing 1 battery kept things smaller and lighter.

    (0) (0)
  3. William (verified owner)

    This Dive light is absolutely amazing. Did a night dive with this light out in a quarry. Loved the ease of use with being able to switch one handed between each feature. I love how big the beam is. Also there is a red light (great for night vision) that I enjoyed using during the dive and on the surface while setting up. The brightness settings are perfect. This is by far my favorite light. In my opinion this SD20 Dive light out competes competitors lights that are listing in the $300 range. I came up next to my buddies and my beam was just as bright if not brighter than his. The rechargeable batteries are a nice addition as you don’t need to spend money replacing them. Loving this purchase. Definitely recommend this dive light for scuba diving

    (2) (0)
  4. Brian Aldouri (verified owner)

    Nice flashlight

    (0) (0)
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What Our Ambassadors Say

Cody F

Fenix SD20 Diving Light Review

Cody F.
Scuba Diving Ambassador, Cody F., Reviews SD20 Dive Light The SD20 dive light is my favorite flashlight because its waterproof up to 100 meters and is very bright. I have gone on over six-night diving trips and never had trouble with the SD20. It’s very dependable, never leaks, running time is amazing (3hrs max 1000…

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