Speras E21

The E21 is a general-purpose flashlight running on an integrated rechargeable 21700 battery. It features a distinctive build, with the popular Luminus SST40 for relatively intense throw.

  1. Introduction
  2. Manufacturer Specifications
  3. Package Details
  4. Build
  5. User Interface
  6. Circuit Measures
  7. Emitter Measures
  8. Beamshots
  9. Testing Results
  10. Runtimes
  11. Pros and Cons
  12. Overall Rating
  13. Preliminary Conclusions
  14. Acknowledgement


I’m still catching up on my backlog – this E21 sample was received early last Fall.

Speras is a new flashlight maker for me. They have released a variety of models over the years, largely focused on the relatively inexpensive consumer market (many with “zoomable” features) or the somewhat higher-end tactical market. I readily agreed to review the E21 when they announced its release last year, given its rather unusual interface.

In terms of performance, the E21 runs on an integrated 21700 battery (i.e., not user-accessible or replaceable) and uses the Luminus SST40 emitter. This emitter is a popular choice for budget throwers, as its relatively small die profile allows for great focusing. The light has a somewhat rakish build, which along with the user interface is likely designed to appeal to the tactical crowd.

Let’s see how it performs in my testing.

Manufacturer Specifications

Note: As always, these are simply what the manufacturer provides – scroll down to see my actual runtimes.

Max Output (Lumens)2,000
Min Output (Lumens)10
Max Runtime220 hours
Max Beam Intensity (cd)26,000 cd
Max Beam Distance (m)322 m
Constant Levels5
Battery1x21700 (integrated)
Weight (w/o battery)-
Weight (with battery)135 g
Length128 mm
Head Diameter25.4 mm
Body Diameter25.4 mm
WaterproofIP68 2m

Package Details

The E21 comes in fairly typical mid-range packaging, with published specs and details on the outside of the box. Inside you will find:

  • Speras E21 flashlight with built-in 5000 mAh 21700 cell
  • Bidirectional pocket clip
  • Wrist lanyard
  • USB-C charging cable
  • USB C to A dongle (for the powerbank feature)
  • Manual

It’s a decent package, but I would still like to see a holster included.

Note that that a gun mount and remote pressure switch option are available to purchase from Speras.


From left to right: Wurkkos 21700 (5000mAh), Vapcell 21700 F56 (5600mAh), Emisar D4K, Wurkkos WK15, Armytek Wizard C2 Max, Wurkkos TS22, Sofrin SC29, Speras E21, Wuben X1 Falcon, Sofirn SC33, Sofirn SP35T, Cyansky P50R, Cyansky P25.

The E21 comes with a bright yellow sticker warning you that the light is locked out, and needs to be unlocked before your first use. A good thing to include, since the integrated battery means you can only electronically lock out the light (which you will definitely want for shipping, or long-term storage).

The E21 is reasonably compact for the class, and is quite comfortable to hold and use. The protruding tailcap switch has a grippy black rubber cover (and so tailstanding is not possible). The switch is distinctive, and actually contains a novel user interface – you can directly press (click) to turn on or off, as well as tap from the side to change modes (or lock/unlock). It takes a bit of practice to get the feel just right for how much side pressure to apply (and where) for this “side switch” feature, but it actually works well once you get used to it. Scroll down to the User Interface section for more info.

The USB-C charging port is located under a translucent rubber cover in the head – which also has a green/yellow/red charge status LED beside it. This cover should provide decent splash-resistance, but I wouldn’t recommend dunking the light in water. There are more labels than typical on this light, including information on the 21700 battery characteristics. According to the Speras website, the E21 uses a LG 21700 INR cell.

I quite like the removable bi-directional pocket clip attached near the base. This allows for both deep-pocket carry, as well as mounting it on something like a ball cap for forward throw. It holds on securely in my testing.

The E21 has a lot of concentric rings on the body, with a relatively smooth head. But with the pocket clip attached, I would say grip is very good. Also thanks to included clip, the light will not roll when placed on its side. Anodizing looks to be good quality, with no damage on my sample (black, but I believe other colours are available). I would describe the finish as matte.

The E21 comes with more aggressive bezel scalloping than typical, likely to appeal to the tactical crowd. Personally, I find these to be something of a gimmick, and more likely to catch on clothing or injure yourself with, but I suppose the E21 would do some damage if you hit someone with it head-on (note the bezel appears to be made of aluminum). Light can still headstand fairly stably.

As expected given the emitter choice, the reflector is relatively deep and smooth. I would expect excellent throw for this model. As you can see above, the centre of the beam is somewhat yellowish/warm tinted, and the edge is bluer/cooler. Scroll down for outdoor pics. There doesn’t seem to be any kind of anti-reflective coating on the lens.

User Interface

The E21 has two sets of possible modes; a general use mode set (called “Outdoor” in the manual), and a tactical model set (appropriately called “Tactical”).

To switch between groups, you actually have to do something a little unusual: you have to connect E21 to an external power source via the charging cable. Another surprise – the light will actually work when plugged into USB (I accidentally flashed myself in the face at full power the first time I tried this). To change between mode sets, you have to side-tap the switch 3 times rapidly. The E21 will blink to confirm the mode set change.

It’s interesting that you can’t change the mode set on the fly, but I suspect that isn’t very common anyway. At least this way you won’t do it accidentally.

Outdoor Mode Set available levels: Eco, Low, Medium, High, Turbo, Strobe.

Outdoor Mode, from OFF:

  • Press-and-hold: Momentary On in last memorized constant output mode.
  • Single-click: Turns On in last memorized constant output mode.
  • Side-press-and-hold: Momentary Eco mode.

Outdoor Mode, from ON:

  • Single-click: Turns Off.
  • Side-press-and-release: Steps up to the next constant output mode (in sequence, Eco > Lo > Med > High > Turbo).
  • Side-press-and-hold: Strobe.

Outdoor Mode memory:

Yes, for constant output modes.

Outdoor Mode Shortcuts:

  • Eco mode: Press-and-hold the side switch from Off.
  • Strobe mode: Press-and-hold the side switch from On.
  • Note there does not seem to be any way to rapidly access Turbo.

Tactical Mode Set available levels: Turbo and Strobe.

Tactical Mode, from OFF:

  • Press-and-hold: Momentary On in Turbo.
  • Single-click: Turns On in Turbo.
  • Side-press-and-hold: Momentary Strobe mode.

Tactical Mode, from ON:

  • Single-click: Turns Off.
  • Side-press-and-hold: Strobe.

Tactical Mode memory:

No, it is always Turbo only.

Tactical Mode Shortcuts:

  • Strobe mode: Press-and-hold the side switch from On.

Battery indicator:

When first activating the light, the indicator on the side switch shows the battery voltage for a few seconds, as follows:

  • Solid green: ~70-100%
  • Solid yellow: ~30-70%
  • Solid red: ~10-30%
  • Flashing red: 0-10%

Low voltage warning:

Not that I noticed.

Lock-out mode:

Yes, but electronic only – side-tap the switch 6 times to lock out the light. Side-tab the switch 3 times to unlock.

Reviewer Comments:

Although the side-press feature takes a little getting used to (both in terms of the exact location and amount of pressure to apply), I find this interface to be pretty decent. On the general “Outdoor” mode, you can easily access everything you need to (although it does lack a shortcut to Turbo).  In Tactical mode, it is a very simple Turbo light with immediate access to Strobe.

You just need to remember how the lockout feature works, as I recommend you lock out the light when not in use to limit the (unknown) standby drain.

Circuit Measures

No Pulse-Width Modulation (PWM):






There is no sign of PWM at any level, the circuit appears to be fully current-controlled. There is also no circuit noise on any level, which is a sign of a decent circuit.



Strobe alternates between 7 Hz and 17 Hz every ~2 secs or so. Very disorienting and distracting (i.e. “tactical”).


There is a small LED by the charging port which shows solid red when the light is charging. Changes to solid green when the charging is complete.

Heavily depleted:

After a couple of seconds:

The E21 doesn’t seem to have a two-stage charging feature, as seen on many modern lights (i.e., where there is a lower initial charging rate when the cell is heavily discharged). The initial charging rate here is ~1.55A, and it rapidly increases from there to ~1.65A over the first 30 secs or so of charging. This is a decent charging rate for the class, and will charge a 21700 cell quickly.

Standby / Parasitic Drain:

The main switch feels like a physical clicky switch (but may not be), however the side-press feature is clearly electronic (thus requiring a standby drain). Also the, USB port is by definition always active. Due to the sealed physical build, I wasn’t able to measure the standby current. I recommend you store the light locked-out when in not in use, to prevent accidental activation (and hopefully lower the standby current).

Powerbank Feature:

With the included USB C-to-A adapter, you can turn the E21 into a powerbank to charge other devices. I measured a charging current of ~1.2A for my Samsung phone, using the included USB charging cable.

Emitter Measures

In this section, I directly measure key emitter characteristics in terms of colour temperature, tint, and colour rendition. Please see my Emitter Measures page to learn more about what these terms mean, and how I am measuring them. As tint in particular can shift across levels, I typically stick with the highest stably regulated level for all my reported measures.

As explained on that page, since I am using an inexpensive uncalibrated device, you can only make relative comparisons across my reviews (i.e., don’t take these numbers as absolutely accurate values, but as relatively consistent across lights in my testing).

E21 on Hi:

The key measures above are the colour temperature of ~5450K, and a positive tint shift (+0.0158 Duv) to a greenish-yellow at this temperature. For CRI (Ra), I measured a combined score of 58.

These values are consistent with the performance of the Luminus SST40 in my experience. Note that there is a tint shift to more cool by the spillbeam edge on my sample.


All outdoor beamshots are taken on my Canon PowerShot S5 IS at f/2.7, 0.5 secs exposure, ISO 400, daylight white balance. The bend in the road is approximately 40 meters (~45 yards) from the camera. Learn more about my outdoor beamshots here (scroll down for the floody light position used in this review).

Click on any thumbnail image below to open a full size image in a new window. You can then easily compare beams by switching between tabs.

The Convoy S21E (with SST40) is the closest comparable for the beam profile. As you can see above, the E21 has greater overall output on Turbo, and has greater centre beam throw. Spillbeam width is a little narrower. Both of these are consistent with the deeper reflector on the E21.

Testing Results

My summary tables are generally reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. In addition to the links above, please see my output measures page for more background.

All my output numbers are based on my home-made lightbox setup. As explained on that methodology page, I have devised a method for converting my lightbox relative output values to estimated lumens. Note that my lightbox calibration runs higher than most hobbyists today, but I’ve kept it to remain consistent with my earlier reviews (when the base calibration standard was first established). On average though, I find my lumen estimates are ~20% higher than most other modern reviewers.

My Peak Intensity/Beam Distance are directly measured with a NIST-certified Extech EA31 lightmeter.

E21 Testing Results

ModeSpec LumensEstimated Lumens @0secEstimated Lumens @30 secsBeam Intensity @0secBeam Intensity @30secsBeam Distance @30secsPWM/Strobe FreqNoise FreqCharging Current <3VCharging Current >3VParasitic DrainWeight w/o BatteryWeight with BatteryCCT (K)DuvCRI
Eco102323---NoNo1.55 A1.60 AYes (not measured)-135 g---
Low100175175---NoNo1.55 A1.60 AYes (not measured)-135 g---
Medium350555550---NoNo1.55 A1.60 AYes (not measured)-135 g---
High9001,7001,600---NoNo1.55 A1.60 AYes (not measured)-135 g5,4500.015859
Turbo2,0003,0002,75033,500 cd30,500 cd349 mNoNo1.55 A1.60 AYes (not measured)-135 g---
Strobe------7-17 HzNo1.55 A1.60 AYes (not measured)-135 g---

The E21’s initial output levels are coming out much higher in my lightbox than the specs indicate, which is unusual. I know my lightbox’s relative calibration is generously high, but max output visually does seem more consistent with ~3000 lumen lights than ~2000 lumen lights. And my NIST-calibrated luxmeter (which is accurately calibrated to an absolute standard), similarly reports greater throw on Turbo than the specs report.

Taken together, it is clear to me that my E21 is outperforming specs for initial output. But check out my actual Runtimes for a clearer picture.

To view and download full testing results for all modern lights in my testing, check out my Database page.


As always, my runtimes are done under a small cooling fan, for safety and consistency. To learn more about how to interpret runtime graphs, see my runtimes methodology page. Note that on average, my lightbox’s calibration seems to be ~20% higher than most modern reviewers.




One key observation is that the E21 steps down significantly on both Turbo and Hi – to lower Med level than most lights use.

The second observation is that the light doesn’t use a flat voltage-regulated circuit, but seems to largely rely on the internal resistance of the internal cell (i.e., direct-drive). This is not necessarily a problem, as it can still be efficient (and appears to the eye as perfectly stable).

Here is a blow-up of the first few mins of runtime on Turbo/Hi output:

As you can see, the E21 steps down to the Med level after 1 min on Turbo, or 2 mins on Hi.

Pros and Cons

The light has higher initial output than the specs indicate.Circuit is not voltage-regulated, producing a slowly decreasing output instead of flat runtimes.
The circuit performance shows very good output/runtime efficiency.Turbo/Hi steps down further than most lights in this class (i.e., all the way down to Med)
The light throws a more throwy beam than most in this size/class.There is some tint shifting across the beam, with a yellowish hotspot and cool white spill.
Innovative switch and user interface, but it may not be to everyone's likingThe integrated cell can't be changed, and the light can only be locked out electronically (i.e., impossible to break to current draw).
Light can serve as a powerbank.

Overall Rating

Preliminary Conclusions

The E21 is an interesting light, with a number of good characteristics – but some limitations as well. Let’s start with the build – physically, it is a solid light, with good handfeel and clip, and distinctive switch. But it also has an integrated battery than cannot be changed – or physically locked out (i.e., there will always be a standby current).

The user interface features two mode sets, which provides some options for you. But I miss having a shortcut to Turbo in the general Outdoor mode set. I personally like playing with the side-press feature of the switch, but it may not be for everyone.

Circuit-wise, the light lacks flat-stabilized regulation. It does run for an extended runtime compared to other light I’ve tested with this emitter, but that’s only because it steps down to a lower level than most lights (i.e., both Turbo and Hi step-down to the relatively low outpit Med level after 1-2 mins).

It is a relatively throwy light, with great throw for the compact 21700 class. But the tint shift in the centre beam is definitely on the greener side (could just be my sample, but it may also have to do with the emitter/reflector combo).

As always, it comes down to what you are looking for and whether a given light meets your needs. I considered giving this light 4 stars overall given its innovative switch design and generally good performance. But the integrated battery in particular brings it down in my view. I’ve enjoyed handing it – but it may not be for everyone.


The E21 was supplied by Speras for review. As always, all opinions are my own and the light received the same rigourous and objective testing as all other lights that I have reviewed. At the time of review, this light retails for ~$63 USD (~$85 CDN) on the Speras website here.

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