G Pen Gio
Pros
- Nothing to clean: the mouthpiece is part of the pod and goes with it
- 16 by 10 by 104 mm and about 41 g
- Draw-activated, with no warm-up and nothing to set
- Pod, coil and battery designed as one assembly
- Serial numbers on device, pod and box that the manufacturer will verify
Cons
- Pods are sold in a limited number of states and shops
- Committed to one company’s oil, with no alternative
- No temperature setting at all, for better and worse
- Not refillable, and should not be treated as if it were
- Micro-USB rather than USB-C
What the Gio is
A slim battery that takes pre-filled cannabis oil pods. There is no button, no temperature setting and no tank. You align the pod with the battery, it holds on magnetically, and you draw. That is the entire interface.
A closed system, by design
The pod, the coil and the mouthpiece are one sealed unit made by the same company that made the battery, which is the opposite of the open 510-threaded market where any cartridge goes on any battery. Closed systems are less flexible and more predictable, and predictability is worth more here than most reviews allow.
The size and the weight
16 by 10 by 104 mm and about 0.09 lb, which is roughly 41 grams. It is the smallest device in this range by a wide margin and it disappears in a pocket in a way the G Pen Pro does not quite manage.
No buttons, no settings
Draw-activated, with no warm-up wait because there is nothing to warm up until you inhale. There is also nothing to adjust, which is either the best or the worst thing about it depending on what you wanted.
What the pods hold
0.5 ml of cannabis oil, in a child-resistant package that states the strain and the cannabinoid content. They are not designed to be opened or refilled, and attempts to do so are the kind of thing that turns a sealed system back into an open one with none of the safeguards.
About a hundred draws
We got roughly a hundred draws from each pod, which lines up with what 0.5 ml should give. That is a more useful figure than millilitres, because it is the one you can compare with how often you actually use it.
Why the mouthpiece stays clean
The mouthpiece is part of the pod rather than part of the device, so it is replaced every time the pod is. There is no cleaning, no residue in an airway and no cotton bud. On a device you carry every day, that is a larger practical advantage than it sounds.
Temperature control matters here
This is the part no other review of this device covers, and it is the strongest argument for a closed system. Oar and colleagues pointed an infrared camera at cartridge coils through a simulated puff. A temperature-controlled pod system held 420 ± 9.5 °C at its top setting and 246 at its lowest.
What a loose battery does
The same study measured voltage-controlled batteries: 4.0 V averaged 543 ± 95.9 °C, 2.4 V averaged 443 with a deviation of 56, and a fixed 3.2 V battery averaged 450 with a deviation of 61. Read the deviations. A system that manages its own temperature varied by about ten degrees between puffs; ones that apply a voltage to a coil varied by fifty to a hundred.
That is the case for matched hardware in one number. It is not a claim that this particular device is temperature-controlled to that standard — Grenco publish no figure — but it is why a pod designed for the battery it sits on is a different proposition from a cartridge bought separately and screwed onto whatever was in the drawer.
The serial number on the base
The device, the pod and the box all carry a serial number, and the manufacturer will check it. It is presented as a warranty mechanism. It is more useful than that.
Why that is the real feature
Counterfeit cartridges are the central risk in this category and packaging is cheap to copy. A serial number the manufacturer can confirm, on a pod you bought from a licensed shop, is a harder thing to fake than a logo. During the 2019 vaping outbreak, among patients who named a source for their THC products, 78 per cent had used only informal sources against 16 per cent who had used only commercial ones. We go through that in full on THC cartridges.
Where you can actually buy pods
Licensed dispensaries in legal states, and not everywhere even then. When this device launched the pods were in a handful of shops in two states; the map has grown since and it is still nothing like nationwide. Check before you buy the battery, because the battery is worthless without them.
The availability problem
This is the thing that should decide it for most people. A closed system means you are committed to one company’s pods, sold through one channel, in the states where that channel exists. An open 510 battery will take a cartridge from anyone. That flexibility is exactly what the temperature data above argues against, and it is still the practical reality of owning one.
Not refillable, on purpose
You cannot top a Gio pod up, and the reasonable-sounding workarounds are not worth attempting. Reopening a sealed pod puts an unknown oil onto a coil calibrated for a different one, which is the whole failure mode a closed system exists to remove.
Charging, and the light
A micro-USB port in the base and roughly two hours from empty. A light flashes while it charges and goes out when it is done. For a device that heats only while you draw, the battery lasts considerably longer between charges than a flower vaporizer will.
Against the PAX Era
| G Pen Gio | PAX Era | |
|---|---|---|
| System | Closed, magnetic pod | Closed, magnetic pod |
| Temperature | Fixed, no setting | Adjustable through an app |
| Pod range | Narrower | Much wider |
| Availability | Fewer states | Broader |
| Interface | Nothing to learn | A phone, if you want the settings |
The Era has the larger pod catalogue and the settings. The Gio is simpler and smaller. If you are choosing on what you will actually be able to buy locally, that question answers itself before any of the rest matters.
What the vapour is like
Good, and largely a function of the pod rather than the battery, which is the honest way to review a closed system. Flavour varies more between pods than it does between this and its competitor, so a judgement about the device is mostly a judgement about whose oil you can get.
Who it suits
- Anyone who wants nothing to clean, learn or adjust.
- Anyone living where the pods are actually stocked.
- Anyone who would rather the manufacturer chose the coil temperature than a battery in a drawer.
Who should look elsewhere
- Anyone outside the states where pods are sold, for whom this is an ornament.
- Anyone who wants to choose their own oil, which means an open 510 battery and the judgement that goes with it.
- Anyone vaporizing flower, which this does not do at all — see vaporizers.
Verdict
Judge this one on the pods, not the battery. As hardware the Gio is close to faultless for what it is — nothing to clean, nothing to set, small enough to forget about — and the sealed design is a genuine safety argument rather than a marketing one, because a pod, coil and battery built together take the coil temperature out of the buyer’s hands. Thermography of cartridge hardware found voltage-controlled batteries varying by up to a hundred degrees between puffs. The catch is entirely commercial: you are committed to one company’s pods, sold in a limited number of places. Check what you can buy near you before you buy the battery.
Questions people ask
Can you refill G Pen Gio pods?
No, and it is not worth trying. The pods are sealed units in which the coil was matched to the oil that was put in at the factory. Reopening one puts an unknown oil onto that coil, which is precisely the failure a closed system is designed to remove, and it voids any recourse you had.
Where can I buy G Pen Gio pods?
Licensed dispensaries in legal states, and not in all of them. The distribution started in a handful of shops across two states and has widened since without becoming anything like nationwide. Check what is stocked near you before buying the battery, because the battery is of no use without pods.
How many hits do you get from a G Pen Gio pod?
About a hundred from a 0.5 ml pod in our use, which is a more useful figure than the volume because it maps to how often you actually reach for it. It varies with how long each draw is; the device heats only while you inhale, so a short draw uses proportionally less.
Is a closed pod system safer than a 510 cartridge?
It is more predictable. Infrared thermography of cartridge coils found a temperature-controlled pod holding 420 °C within about ten degrees, while voltage-controlled batteries averaged 443 to 543 °C and varied by fifty to a hundred between puffs. What matters more than either is where the product came from: among 2019 outbreak patients who named a source, 78 per cent had used only informal ones.
Sources
- Oar MA, Savage CH, Rufer ES, Rucker RP, Guzman JA. Thermography of cannabis extract vaporization cartridge heating coils in temperature- and voltage-controlled systems during a simulated human puff. PLoS One. 2022;17(1):e0262265. accessed Sep 18, 2026
- Outbreak of Lung Injury Associated with the Use of E-Cigarette, or Vaping, Products. Centers for Disease Control and Prevention. Final case counts as of 18 February 2020. .gov accessed Sep 18, 2026
- Krishnasamy VP, et al. Update: Characteristics of a Nationwide Outbreak of E-cigarette, or Vaping, Product Use-Associated Lung Injury - United States, August 2019-January 2020. MMWR Morb Mortal Wkly Rep. 2020;69(3):90-94. .gov accessed Sep 18, 2026
