Fenix E03R

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Fenix E03R review


Brand/modelFenix E03R
CategoryKeychain lights
LEDMatch CA18 (white)+ Everlight 2835 (red)
Lumens260 lm
Beam intensity441 cd
Battery config.built in
MaterialAll metal
ModesWhite:4 + red: 2
Blinkiesred flash
Review dateJanuary 2021


Besides the vast amount of Tactical Flashlights, Fenix also produces cute little keychain lights like the Fenix E03R. It’s a very lightweight “all-metal keychain flashlight”, according to Fenix. I have a few other keychain flashlights reviewed in the past, so I’m quite interested in seeing how this mini flashlight performs. I know we lack keychain flashlight reviews, so I bought myself a few keychain flashlights for testing.

Package quality.

The Fenix E03R was delivered in a disposable package. You can’t really re-use it after opening. This is what you get:

  • The Fenix E03R
  • USB-C charge cable
  • Small attachment ring
  • Manual
  • Warranty card
  • Mini brochure

Handling of the light

Of course, I knew I was going to review a keychain light, but some of them are just really really small. The E03R is small and very lightweight. But it looks like the perfect keychain flashlight. It’s not made of plastic and it’s flat. Most keychain flashlight with AAA batteries can still be a bit too long, while others are too thick for most people.

The package includes a small metal ring to attach to your keys. The switch is small as well and sits flush with the body. Although the switch might be difficult to locate in complete darkness, you just grab on to the light towards the front and pinch. The light should turn on if it’s not locked out.

Build Quality, and Warranty

The manual states: All-metal CNC machining light body. And I guess that means it should be pretty strong. I hit it a few times against the table, and it looks durable. And I agree that this is probably a tough bugger.

I can’t really say anything negative about its anodization either. It looks great, all around the flashlight. I kind of like the color of the coating. This coating is supposed to be: Premium type HAIII hard-anodized anti-abrasive finish. It’s funny how they describe the coating in so much detail.

Warranty: 5-year free repair. Fenix will repair a light free of charge within 5 years (non-detachable light: 2 years, rechargeable battery and other accessories: 1 year) of purchase if problems develop with normal use.

Lifetime maintenance: if repair required after 5 years, from the date of purchase, Fenix will charge for parts. The total repair fee is dictated by the cost of the replaced materials.

This means that they guarantee to have replacement parts even after 5 years.


At the business end of the flashlight are 2 small TIR optics. 1 shows a yellowish LED and the other shows a red LED. The diameter of the actual optic is about 7mm. So don’t expect any miracles in terms of throw distance. The beam is smooth, as you can expect with this type of optics.

Since I can’t open it up, there is not much else to say.

The manual states the white LED being: MATCH CA18 white LED, and Everlight 2835 red LED.


  • Length:  46.48 mm / 1.83”
  • Body diameter: 23.79  mm / 0.937 ”
  • Body thickness (thickest part): 11.54 mm /  0.454”


  • Weight: 22 g /  0.78 oz

Keychain flashlight size comparison

Size compared to other tiny keychain flashlights.

From left to right: Lumintop EDC AA, Reylight Pineapple Mini, Fenix E12 v2, Nitecore TUP, RovyVon Aurora A9 CU, Fenix E03R

Driver & User Interface:

What driver:

The Fenix E03R has 4 modes with the white LED, and 2 modes with the red LED

Available modes:

  • White LED: 4 modes: Eco, Low, Med, High
  • Red LED: 2 modes: On, Flashing

From OFF:

  • Single-click:  battery check
  • Press and hold 1 sec: Eco
  • Press and hold 2 sec: Red LED
  • Double click: lock-out mode (the white LED blinks 2 times to indicate the lockout is activated, repeat to deactivate)

From ON:

  • Single-clicks: run through the menu from Eco to High
  • Press and hold 1 sec: Off
  • Press and hold 2 sec: Red LED (do a single click to move from constant on to blinking red)

Mode memory:

  • There is no mode-memory

Blinky modes menu:

  • Only available with the red LED. Press and hold the flashlight for 2-3 seconds until the light turns red. Then use a single click to move from constant on to flashling/blinking.

Battery check:

  • There is a small indicator LED in the switch. When the light is turned off, and you click 1 time, you can see the battery status for 3 seconds:
    • Constant green: 70-100%
    • Blinking green: 40-70%
    • Constant red: 10-40%
    • Blinking red: 1-10%

Lock-out mode:

  • A double click will activate lockout mode.


  • Not visible by eye


I don’t think it’s a bad UI if you are used to it. I’m not used to it, so I had trouble getting it to work without making mistakes. A keychain light with a side switch is doomed to turn on in your pocket accidentally, so the lockout mode is not a luxury but a necessity. Press and hold for Off isn’t the best, since you can accidentally turn on the red LED when you press the switch too long. I would have preferred a secondary switch just for the red LED.

Batteries & Charging

Charging is done with a USB-C charging cable. The cable is included, the USB charger isn’t. The charge current is roughly 0.2A and the flashlight can be used while charging. I’m not sure if that is okay to do, since the manual doesn’t mention anything about it.

The built-in battery is a 200mAh Li-polymer battery. Charging takes about 1 hour.


Lumen measurements:

All output numbers are relative for my home-made Integrating Sphere. It is set up with an Extech SDL400 Lux Meter for measurements including a Kenko PRO1D ND-16 filter. The base measurement is done with a Convoy S2+ that has been tested at 255 lumens.

Modespecified30 secstart
Med8080 lm82
High260 lm256 lm272 lm

My measurements were pretty close to the specs, and the .74 lumens higher is actually just 1 lux on the luxmeter, if I didn’t use the ND filter, it would have been more accurate. The current setup is not great for low output numbers. But I got a second styrofoam ball to make my seconds integrating sphere.


The runtime test was done with the 50cm integrating sphere, including the Kenko Pro1D ND-16 filter and Extech SDL400 data logging Lux Meter.

High mode drops to about 125 lumens within 3 minutes and has a total runtime of 40 minutes. At that point it steps down, and down, and continues to run for another hour or so at 2 lumens or so. I would not recommend using it till it dies, but recharge it before it runs completely flat.

Medium starts off around 80 lumens and slowly drops in output, with a total runtime of 1 hour and 12 minutes. The output drops to roughly 15 lumens for 1 minute. It then drops again and continues at a low output (2 lumens) for another 40-50 minutes.

Low starts around 30 lumens and then slowly drops is to about 15 lumens in 3 hours and 2 minutes. It then drops to a few lumens and continues running for 30-40 minutes

Eco runs straight for almost 18 hours.

Throw Measurement

Measurements were taken indoors at 5 meters with a professional Hagner E4-X Lux Meter.

ModeCandela specsCandela measuredMetersYards
High441875 cd5965
High 30 sec800 cd5762

It performed above specs in terms of throw capabilities.


For the following beamshots I used a Canon EOS 5D Mk2 and a 50mm lens. manual settings: ISO1600, 1/30sec , F4, 5000K

Disclaimer: I bought this flashlight with my own money. Nobody paid me to review this flashlight, nor have I been holding back on problems or defects. 



  1. Pretty solid
  2. The output is great for its size and battery
  3. Lockout mode is required and useful


  1. UI isn’t the best
Author: Marco

4 stars: ★★★★

I would give this 4 stars. The output and runtime are good for this size of a flashlight. But I wished it had a better UI. The press and hold for off, sometimes activates the red LED if you press it too long. Other than that, this is a nice and solid keychain light!

Fenix E03R discount code

Also, check out our review of its successor, the Fenix E03R v2

But at Fenixlighting with 10% off, by using our exclusive discount coupon: 1lumen10

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