Eleaf iStick X40 + GTL X Tank Preview — Swappable Battery, MTL Done Properly
Most MTL kit makers seem to have agreed on built-in batteries. Eleaf haven’t got that memo — and for a lot of vapers, that’s going to be exactly the right call.
The iStick X40 is the newest entry in Eleaf’s iStick Series, and it ships with the brand’s upgraded GTL X Tank.
The headline feature is a removable 3000mAh battery — the kind you can swap out mid-day rather than hunting for a USB port. Announced in early July 2026, it’s landing at a point when the UK market is awash with sealed pod systems, and Eleaf is quietly offering something genuinely different.
The Battery Situation
Three thousand milliamp hours via a removable cell is the standout spec here. Eleaf claim up to three days of heavy use on a single charge — a bold claim that real-world use will ultimately test — but more importantly, if you’ve got a spare battery, you’re never stuck. Charging runs via USB-C at 5V/2A, which keeps topped-up times reasonable if you’d rather plug in than swap.
Output runs from 5W to 40W, covering everything from a tight, cool MTL draw at low wattage through to a slightly warmer, more open vape at the top end. There’s no auto-watt here — you dial in what you want via the fire button and lock/unlock switch, with a 1.05-inch TFT colour screen showing battery level, puff count and coil resistance. The screen comes with five customisable themes, which is a small touch but a welcome one.
One more thing worth noting: the iStick X40 supports firmware upgrades via PC, which means Eleaf can push performance improvements down the line without you needing to buy new hardware.
The GTL X Tank
The GTL X Tank is where a lot of the design thinking has gone. Both the fill port and the airflow sit at the top of the tank — and that combination matters. Top-fill is simply cleaner and faster than bottom-fill.
Top airflow significantly reduces the chance of e-liquid sitting against the seal and eventually leaking through. It’s a practical pairing that you’d think would be standard by now, but still isn’t universal.
The slide-open fill mechanism is one-handed — push to reveal the port, fill, close. Capacity is 3ml on the UK TPD version, with an optional glass tube upgrade taking it to 4.5ml for markets without the restriction.
The airflow control ring is adjustable and sits precisely enough to hold your setting.
What Coils Does It Use?
This is where existing Eleaf owners will be pleased. The iStick X40 is compatible with the full GTL coil range — an established ecosystem covering everything from tight MTL to a more open draw.
The kit ships with two of the newer GTL-D dual mesh coils: a 0.8Ω option for a warmer, slightly fuller vape and a 1.2Ω for a cooler, tighter draw.
Both are described as using high-quality heat-resistant cotton with optimised mesh structure, which is Eleaf’s claim for improved lifespan and consistency versus their previous coil generation.
Specs at a Glance
- Battery: 3000mAh removable
- Output: 5–40W
- Screen: 1.05-inch TFT colour, 5 themes
- Tank capacity: 3ml (TPD UK) / 4.5ml with glass tube
- Fill: Top slide-open
- Airflow: Adjustable top airflow
- Charging: USB-C, 5V/2A
- Coil compatibility: Full GTL range + new GTL-D dual mesh
- Included coils: GTL-D 0.8Ω + GTL-D 1.2Ω
- Dimensions: 36.7 × 24.4 × 129.5mm (3ml tank)
- Firmware: Upgradeable via PC
- Colours: Silver, Black, Blue, Gold, Pink
Worth a Look?
If you’re already in the Eleaf ecosystem with a stock of GTL coils, the X40 is a straightforward next device — the coil transition is seamless and the upgrade to GTL-D dual mesh is a genuine improvement.
For anyone new to Eleaf, the removable battery and broad coil range make it a low-fuss, long-term proposition rather than something you’ll outgrow in six months.
Full hands-on review to follow once a unit is with us.
