Introduction – The iJust 21700 Kit by Eleaf

The Eleaf iJust 21700 is a large pen style mod that holds a removable battery. The kit comes complete with the Ello Duro tank as a topper.eleaf-ijust-21700 header

Eleaf Electronics Co Ltd started life way back in 2011 in China. They bought us the ever popular iStick series – 20w30w50w100TC plus more. Eleaf have a huge product list far, too many to list here, but some of their products include iStick Pico X, Elven Pod, Pico Squeeze 2 and iStick Nowos.

Eleaf normally release pen style devices with an integrated battery so this makes the iJust 21700 just different enough to stick out from the crowd.Eleaf iJust 21700 down lay

So what do we think of the Eleaf iJust 21700 Kit? Let’s go and take an up and close look at it!

This product was sent to us for the purpose of review. As always my thoughts and views are my own after a considerable testing period.

Check Out The Eleaf iJust 21700 In Action

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In The Box

  • Eleaf iJust 21700 mod
  • 21700 Battery (optional)
  • 18650 Battery Adaptor
  • Eleaf Ello Duro tank
  • HW-N2 0.2ohm coil
  • HW-M2 0.2ohm coil (pre installed)
  • QC USB cable
  • Manuals
  • Spare partsEleaf iJust 21700 kit

Main Specs/Features

  • Size:25x148mm (5.5ml version) or 25×130.5mm (EU Version)
  • Battery: Single 21700 / 18650
  • Output wattage: 80W max
  • Resistance range: 0.1-3.0Ω
  • Tank capacity: 5.5ml (standard) / 2ml (EU)
  • Slide top fill – locking top cap option
  • Coils: Eleaf HW range
  • Leak proof and self cleaning technology
  • LED battery indicator
  • Compatible with tanks up to 25mm diameter

Design and Build Quality

The iJust 21700 kit comes in a card box with a paper over sleeve, the kit includes the battery case and the Ello Duro + extras.Eleaf iJust 21700 in box

My first thought when opening the box was “bugger” they’ve sent me the 2ml EU tank! Eleaf iJust Ello DuroBasically 2ml tanks and I don’t mix very well especially with sub ohm coil heads; I tend to spend more time with a bottle in my hand filling rather than vaping LOL.

The Ello Duro Sub Ohm Tank

The main structure of the tank is identical to the tank that comes with the iJust 3. Eleaf have been including the Ello Duro with quite a few of their releases in recent months. This version of the tank is made of stainless steel with a resin tank that has an inlaid pattern.Eleaf iJust Ello Duro 2ml tankThe fill port has a slide to the side function with the tanks available in the 2ml (TPD) I received or 5.5ml sloped tank for you lucky so and so’s outside Europe.Eleaf iJust Ello Duro fp Some versions of the tank have a lockable fill port (again depending on which you purchase).

The 510 mouthpiece is made of resin and has an inlaid pattern.Eleaf iJust Ello Duro mp fpWhen I first opened the box the thought struck me that both the tank and the mouthpiece were damaged, they weren’t, the look is due to the patterning, btw you do get a spare 2ml Pyrex tank in the box.

The airflow is a wide tri cylon type (one side mirrors the others as it’s turned). Eleaf iJust Ello Duro af triMy tank is of good quality and good design even if it’s only 2ml LOL.


The coils that Eleaf send along with this kit are from the HW range “HW-M2 and HW-N2”, Eleaf iJust Ello Duro outside coilsBoth coil are 0.2Ω and rated at 40 to 90w and incorporate a new porous cotton, for better flavour and wicking; the airflow travels through the centre of the coil for a greater flavour.header coil I have never seen coils like these, they are very interesting; they have the normal cotton and mesh coil but through the centre they have a post.Eleaf iJust Ello Duro inside coils

Innovative Leakage-Proof & Self-Cleaning (LPSC) Technology

Eleaf state:

The new HW-M2 and HW-N2 coils are both designed with a leakage proof structure. There will be no leakage even after you leave the atomizer stand for a rather long time. What’s more, the bottom of the new coil is designed with multi-holes for fully absorbing the condensation. This design further prevents e-liquid leakage and reduces cleaning work of atomizer.

The 21700 Battery Case

Made of aluminium with stainless steel top and bottom caps, I say battery case because the body of the kit can take either 21700 or 18650 batteries using the included battery adaptor. Eleaf iJust 21700 bat adThe connection point has SS threading that is well turned and a gold plated spring loaded pin.Eleaf iJust 21700 pinEleaf iJust 21700 thread 510The bottom cap or battery cap has the usual safety marks, as well as a small hole for battery venting.Eleaf iJust 21700 info The cap is threaded and the inside is gold plated.Eleaf iJust 21700 thread capLooking into the tube you will see the battery orientation indicator a Red +.Eleaf iJust 21700 red xThe body of the tube is decorated with a straight grooved pattern, the branding has been engraved into the mod  with “Eleaf” one side of the tube.Eleaf iJust 21700 adv 1And “iJust 21700” the other.Eleaf iJust 21700 adv 2The rear of the device has a top seated micro USB charge point; making it easy to charge your battery while the mod stands on your desk.Eleaf iJust 21700 usbThe front has a large SS fire button with LED lights under it so you can keep an eye on your remaining battery charge level.Eleaf iJust 21700 fire

All threads have been turned well, the device is very comfortable to hold, the design is very good and the manufacturing quality is exemplary.

Quick Start Guide / Setting up the iJust 21700

I recommend emptying the Ello Duro tank before changing coils or you will find you will create a big mess lol.

Ello Duro

  • Unscrew the bottom cap and screw in one of the coils into the coil cupEleaf iJust Ello Duro cup
  • Pre wick the coil by dropping a few drops of e-liquid onto the cottonEleaf iJust Ello Duro wick
  • Reassemble the tank
  • Push open the top fill port and fill with your liquid (I always close the airflow while filling).Eleaf iJust Ello Duro fill

Set the tank to one side for a few minutes so it can soak up more e-liquid.

Eleaf iJust 21700

  • Choose which battery type suits you and install it (18650 use the battery adaptor)Eleaf iJust 21700 18650 adp
  • The battery only goes in one way positive downEleaf iJust 21700 batt
  • Re-screw the battery cap back into positionEleaf iJust 21700 cap screw
  • Screw on your Ello Duro (don’t forget to open the AF)Eleaf iJust 21700 hand

Done you are now ready to enjoy the Eleaf 21700 kit.

Battery indicators LED lights

The 21700 mod has 4 different LED’s to help you keep track of the battery discharge.led header


  • These include: Over charge, over discharge, over current, 10 second fire, short circuit and reverse polarity.
  • To turn the device on and off click the fire button 5 times.

The resistance range for this device is 0.1-3.0Ω, the mod has a 25mm diameter so any tank or RDA up to 25mm will sit comfortably on the device.

How Does The Eleaf 21700 Kit Perform?

For this review I am using the pre installed 0.2Ω HW-M2 coil in the Ello Duro tank along with “Moreish Puff” E-liquid called Chilled Mango that has 3mg of Nicotine in it.Eleaf iJust 21700 lay liquid

Battery Life

The Eleaf 21700 mod will fire to a max of 80w, as the battery degrades the wattage drops, however this wasn’t apparent to me until the LED was around 29%.Eleaf iJust 21700 hand com

With a 21700 battery installed, I was able to vape this unit for more than a day without swapping the battery out; with an 18650 battery and adaptor I managed 3hrs.

You can charge your battery via the on board micro USB port – I personally tend to swap out the battery for a freshly charge one and charge the used one in a standalone charger!

Flavour / Cloud

At full charge I will admit I did cough and splutter a bit with the airflow wide open, at first the amount of vapour was tremendous; turning down the AF a bit did help in that regard.Eleaf iJust 21700 toot testThe vapour was warm but not overly so and the flavour with my chilled mango was out of this world. I said in my review for the iJust 3 that it was very much my idea of a decent vape, this one is even more so with the combination of the 80w power and the longevity of a 21700 battery – I’m in vape heaven LOL.

The only thing that lets this kit down for me is the 2ml tank capacity but it is what it is!Eleaf iJust 21700 toot Not that I found anything wrong with the tank its just very thirsty, still there is nothing stopping me putting an RTA or even another sub ohm tank on the battery – which I have done by testing out my Drop Dead RDA, Core RTA and the Freemax Mesh Pro Tank, all of them worked extremely well.

Coil Test

I decided to test the coil and tank for leaks, I did this by setting the tank to one side for a complete day, using the kit from stone cold did not reveal any liquid leak from the AF, I even tilted the tank to one side – no leaks.

I did however find there was a slight gurgle on the puff from cold, but this soon diminished and disappeared as the tank warmed up! I would call the test a success.Eleaf iJust 21700 fingers


  • Good quality
  • Well Designed
  • Vapour and flavour quality
  • Great battery life with a 21700
  • Pocket friendly


  • 2ml tank (No choice in TPD countries)

Final Review Verdict

While the iJust 21700 kit is very similar to the iJust 3 kit, with one major difference the inclusion of the replaceable battery! I favour this one more than its predecessor.

Its comfortable in the hand with only a slight difference of the weight, the only thing I personally I don’t like is the 2ml Ello Duro and while the vapour and flavour is good, it is a pain to keep filled; so in that instance I recommend you buy the 5.5ml version if you can or use a different tank on the mod.

Would I buy the Eleaf iJust 21700 kit should this one become damaged or stolen? Yes I would in fact I’ve already ordered another unit and plan on using them as travel mods in the near future.

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Vapour Production
Design and Build Quality
Battery Longevity 21700
Price Point
Likelihood of re purchase
Hi my name is Kevin, I started vaping back in 2009 mainly because my little boy at 3 years old was starting to copy the way daddy smoked a cigarette! Over the years I have gained a good amount of experience with different types of vaping hardware but I'm just a normal guy who enjoys sharing my experiences. This is why I started my Youtube vape review channel in 2014. To date the channel has had over 500,000 views. Being disabled, vaping has given me a gateway to meeting people from all different walks of life, many of those I would not have met under other circumstances. The way I look at my reviews is, if I can convince just one person to give up the stinky’s my job is done. I class myself as a tinkerer as I like to take things apart to see how they work and put them back together, yes that includes e-cigarette mods! One day I would like to be able to design my own mod. I am a dedicated father, and husband to my sweetheart of nearly 30 years! Family to me comes before anything else.


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