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 Electronics Co Ltd started life way back in 2011 in China. They bought us the ever popular iStick series – 20w, 30w, 50w, 100TC 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.
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
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 parts
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.
My first thought when opening the box was “bugger” they’ve sent me the 2ml EU tank! 
Basically 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.
The 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.
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.
When 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). 
My tank is of good quality and good design even if it’s only 2ml LOL.
Coils
The coils that Eleaf send along with this kit are from the HW range “HW-M2 and HW-N2”, 
Both 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.
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.
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. 
The connection point has SS threading that is well turned and a gold plated spring loaded pin.
The bottom cap or battery cap has the usual safety marks, as well as a small hole for battery venting.
The cap is threaded and the inside is gold plated.
Looking into the tube you will see the battery orientation indicator a Red +.
The 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.
And “iJust 21700” the other.
The 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.
The front has a large SS fire button with LED lights under it so you can keep an eye on your remaining battery charge level.
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 cup
- Pre wick the coil by dropping a few drops of e-liquid onto the cotton
- Reassemble the tank
- Push open the top fill port and fill with your liquid (I always close the airflow while filling).
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)
- The battery only goes in one way positive down
- Re-screw the battery cap back into position
- Screw on your Ello Duro (don’t forget to open the AF)
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.
Protections/Functions
- 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.
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%.
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.
The 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!
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.
Pros
- Good quality
- Well Designed
- Vapour and flavour quality
- Great battery life with a 21700
- Pocket friendly
Cons
- 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.
