Eleaf Istick 40W TC Box Mod Review


Eleaf did a lot to popularise box mods with the original iStick, and the TC40W helped do the same for temperature control.

When it was released last summer most temp control devices were a lot bigger and more expensive, so this reasonably priced little gadget was a big hit.

A year later it’s still on the market, which is pretty good going when you look at how fast the technology’s evolving.

I’ve had one for a while now, and while it isn’t perfect it’s still a decent mod with a few strong points in its favour.




The iStick TC40W comes in a neat and sturdy cardboard box. The top layer holds the mod.

There’s another cut-out, which holds a GS Tank if you ordered the kit; if you didn’t, don’t worry – there isn’t anything missing.

Lift out the foam and there’s a 510 to eGo adapter, USB charging cable and a small instruction manual.

The first thing you’ll notice about the mod itself is that it’s small.

There’s an 18650 battery in there, and Eleaf have pulled off some neat design to fit that and the electronics into such a compact device.

The case is rounded down the back, and the screen and buttons are behind a smoked plastic panel on the front.

Unfortunately the charging port is on the bottom, so you can’t stand it upright while it charges.

This is annoying after Eleaf got it right with the iStick 50. Apart from that it’s a nice device to use.

It fits comfortably in the hand, and it’s small enough to be a useful stealth vape as well.

Eleaf have also paid attention to details. The original iStick had issues with the cheap alloy 510 connector stripping its threads, but the TC40W has a steel connector.

There are airflow slots cut into the top deck for atomizers that draw in through the connector, and two more slots so you can attach a lanyard.

The screen is clear and the buttons are nicely clicky.

Overall it feels like a well-made piece of kit, especially for the price.

It isn’t perfect, though – the fire button is metal, and surrounded by a matching bezel, but on mine (and a couple of others I’ve seen) it’s slightly loose and rattly.

A point to watch is that some people have had issues with the fire buttons on various iSticks, so this seems to be a weak point in Eleaf’s designs.




  • 1 x iStick TC40W e-cig battery
  • 1 x USB charging lead
  • 1 x eGo thread adapter
  • 1 x User Manual




  • Size: 36.2mm x 22.3mm x 77.3mm
  • Color: Black, Blue, Silver, Grey
  • Capacity: 2600mAh
  • Thread type: 510 thread
  • Rated output wattage: 1-40W




The iStick TC40W has two modes; it can run as a standard variable wattage device, or in Ni200 temperature control mode.

The variable voltage mode from earlier iSticks has been dropped, which frankly I don’t think is much of a loss – it couldn’t do anything VW mode couldn’t.

The mod is smart enough to recognise a Ni200 coil, and if it does TC mode is available; otherwise you can set it to TC mode, but as soon as you press the fire button it switches back to VW.

This is a crude but effective safety precaution – running in TC mode with a kanthal coil is a good way to blow up your battery.

The controls are simple.

There are four buttons in all; the large fire button sits above the screen, and below it are the up and down arrows with a third small button between them.

Switching it on is achieved with the usual five quick presses of the fire button, and if you’re using it for the first time that will put you in VW mode.

To change the power just use the up and down arrows to adjust it in 0.1 watt increments.

Your other option – and probably the one that will persuade you to buy this mod – is the TC mode.

This is set up for Ni200 coils, and might not be reliable (or safe) with titanium or stainless steel ones, so stick with nickel.

With a nickel coil fitted, all you have to do is press the small button between the arrow keys for a second or so; the display will change from wattage to temperature.

You can display temperature in °C or °F; just hold one of the arrows and let it scroll through.

When it reaches the limit it will switch to the other measurement. Temperature adjustment is in increments of 5°C or 10°F.

In TC mode, the screen normally shows the temperature you’ve set it to.

When you press the fire button it switches to the actual measured temperature, and it’s quite impressive how fast this rises.

Maximum temperatures are 310°C or 600°F. I found 300°C was ideal – but then I sub-ohm 24mg juice, so my preferences might not be a great guide.

The remaining functions are pretty much the same as earlier iSticks.

To lock the buttons hold up and down together for two seconds; stealth mode turns the screen off and is selected by holding the fire and down buttons.

You can rotate the screen by turning the mod off then holding up and down for two seconds.

Compared to higher end TC mods the iStick 40 is slightly short of features, mainly support for Ti and SS coils, but for most vapers it does what’s needed.

If you’re looking for a first TC device, or something compact for going out, this is ideal.




For such a small mod the screen is a decent size, and it’s bright and easy to read.

There’s also plenty information packed in there, including a battery charge display (which blinks when the mod is charging) alongside resistance, voltage (in VW mode) and wattage (in TC) plus the main display of either watts or temperature.

The screen’s recessed behind its smoked cover, so it’s not very visible from the side, but if you’re looking at it straight on it’s very clear.

The ability to flip it is nice, but although this is pretty simple it does need to be done manually.

More recent mods will flip it automatically depending on which way up you’re holding the device.




The TC40W is powered by a non-removable 2600mAh battery.

In terms of battery life this is okay, but not amazing. If you’ve running above 25 watts or in TC mode it’s not going to last you all day.

On the other hand it is fine for a night out, or to get you through the day at work if you’re not constantly puffing away at your desk.

A full charge takes between three and four hours from a 1A charger, and because the USB port is on the bottom you can’t stand it upright while it charges.

That makes using it as a pass-through awkward, so might want a second device to use while this one charges.



  • TC only works with Ni200 coils
  • Features are limited
  • Bottom-mounted charging port
  • Some people have had the fire button fail




  • Attractively priced
  • Very compact
  • Simple controls
  • Good screen
  • Reasonable battery life




The iStick TC40 can be picked up for under £35 if you shop around, and at that price it’s a decent, basic TC mod.

At the RRP of £43.99 it isn’t quite so tempting; there are more modern devices around for the same (or slightly less) money, which will give you some extra features as well.

On the other hand it does have a built-in battery, which makes it ideal for someone buying their first mod – there’s no need to buy a charger or grapple with the complexities of what battery suits it.

Overall I’m pleased with mine, and still use it regularly, although I have two newer mods on my desk as well.

One reason is its tiny size – there are smaller mods available, but the price for that is much less battery life.

The iStick is, for me, a good balance between size and usability and I’ve been using it quite happily for over six months.

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