These are powered travel coolers, not insulated bags. One runs on USB power or a freezable ice ring with no power at all; the other on a rechargeable battery or continuous USB — and both show the internal temperature rather than asking you to assume it. One is a cylindrical cooler that holds a single pen upright; the other is a hard box that carries twelve 3 ml vials.
Why a displayed temperature changes the job
An insulated bag with a cold pack has one failure mode and it is silent. The pack finishes, the interior drifts up, and nothing tells you. You find out afterwards, if at all. A cooler with a readout converts that into something you can check in two seconds without opening the lid, which also means you stop opening the lid to check, which is the thing that was warming it.
That is the actual argument for powered cooling on a travel day. Not that it is colder, but that it is observable.
Pen cooler, three ways to stay cold
The 3-Mode Pen Cooler is a cylindrical case, 8.5 by 8.5 by 25 cm, that holds a pen upright in a fitted cabin. It cools three ways: indefinitely while plugged into USB (semiconductor cooling), up to about 18 hours from a freezable stainless ice ring with no power at all, and a food-grade bucket that takes ice cubes as an emergency cold source. There is no built-in battery — power comes from USB or the frozen ring. It ships with a carry sleeve and shoulder strap.
The no-power ice-ring mode is the one that matters most in practice. Freeze it the night before and the case holds temperature on a flight with nothing running, nothing to charge and nothing to explain. Upright storage matters too: a pen laid flat rolls and the cartridge shifts, whereas the fitted cabin holds it in the orientation it sits in on the bench anyway. It fits standard 3 ml cartridge pens, including every pen we sell.
Cooler box, capacity and a readout
The Travel Cooler Box is a hard-shell BPA-free ABS case, 208 by 95 by 92 mm, with a magnetic lid and a fitted tray holding twelve 3 ml vials. It runs about 12 hours on a three-cell USB-rechargeable battery, or indefinitely on continuous USB from a wall brick, power bank or car socket. A digital readout on the lid shows the internal temperature across a 0 to 18 degree Celsius range. It ships in an insulated neoprene sleeve that adds a layer on top of the case, and carries as hand luggage. Shipping weight is 2.0 kg.
The fitted tray is doing quiet work: vials that cannot roll do not knock together, and you can see what is still in there without unpacking it.
Which one, and when both
Choose on what is moving. One pen for the day is the pen cooler: it has the no-power ice ring for zero-outlet days, and it fits a bag pocket. A batch of vials is the cooler box: it is the capacity option and the only one with a fitted vial tray and a lid display. They are not competing versions of the same product, and plenty of benches end up with one of each because the trips are different shapes.
When you do not need either
If nothing you carry has a temperature requirement, neither of these is worth the weight or the charging. A hard-shell case from the cases collection protects a pen for a fraction of the bulk. And for a short hop where an ice pack genuinely covers the duration, the passive EVA travel case does the job without a battery. Buy a powered cooler when the exposure is long enough that guessing is the problem.
Handling
Top up the cooler box's battery over USB before a trip rather than after; a battery left flat between uses is the usual reason it underperforms on the day. For the pen cooler, freeze its ice ring well ahead, since a partially frozen ring gives a fraction of its rated hold. Let condensation dry off before closing either case away for storage, and do not store a cooler sealed and damp.
Specifications
| Pen cooler dimensions | 8.5 by 8.5 by 25 cm, cylindrical, fitted upright pen cabin |
|---|---|
| Pen cooler runtime | Indefinite on USB; up to ~18 hours from the freezable ice ring with no power; plus a food-grade ice-cube bucket as an emergency cold source. No built-in battery. |
| Cooler box dimensions | 208 by 95 by 92 mm, hard-shell BPA-free ABS, magnetic lid |
| Cooler box capacity | Twelve 3 ml vials in a fitted tray |
| Cooler box runtime | About 12 hours on a three-cell battery; indefinite on continuous USB |
| Temperature display | Digital readout, 0 to 18 degrees Celsius, on the cooler box lid |
| Included | Carry sleeve with shoulder strap (pen cooler); insulated neoprene sleeve (cooler box) |
| Power | Pen cooler: USB-powered (no internal battery) or the frozen ice ring. Cooler box: USB-rechargeable battery or continuous USB. |
| Intended use | Research, educational, and demonstration transport equipment only |
Pairs with: any pen from research pens, bacteriostatic water vials for the cooler box tray, and the protective carry cases when temperature is not the concern. Each product page carries its live options in the variant picker.
Common questions
What is the difference between the pen cooler and the cooler box?
Capacity and duration. The pen cooler holds a single pen upright, runs on USB or a no-power freezable ice ring (up to ~18 hours), and has a food-grade ice-cube backup. The cooler box holds twelve 3 ml vials in a fitted tray, runs about 12 hours on battery, and shows the internal temperature on a lid display.
Can either be used without power?
The pen cooler can. Its freezable stainless ice ring holds for up to about 18 hours with nothing running, and a food-grade ice-cube bucket adds an emergency cold source. The cooler box needs its battery or a USB supply.
Will they fit in hand luggage?
The cooler box carries as hand luggage, and the pen cooler ships with a sleeve and shoulder strap sized for a bag. Airline rules on batteries vary, so check with your carrier before travelling.
Do they fit the pens sold here?
Yes. The pen cooler's fitted cabin takes standard 3 ml cartridge pens, including every pen in the research pens collection. The cooler box tray is sized for 3 ml vials rather than pens.
Do I actually need a powered cooler?
Only if something you carry has a temperature requirement and the exposure runs long enough that an ice pack would finish first. For mechanical protection alone, a hard-shell carry case is lighter, cheaper and needs no charging.
What do these cases claim about their contents?
Nothing. They are temperature-controlled containers sold as research and educational transport equipment. They make no claim about any material stored inside them, and are not for human or veterinary use.
From The Lab
Everything in this collection is sold for research, educational, and demonstration use only. Nothing here is a medical device, nothing is sold sterile, and nothing is for human or veterinary use of any kind. Not evaluated by the FDA. Nothing on this page is dosing guidance. 21+.
Shipping and delivery
Free shipping on US orders of $80 or more and on international orders of $100 or more. Below those minimums the exact shipping rate is shown at checkout before you pay.
Where we ship: worldwide, fully tracked. International orders may be charged import duties or taxes by the destination country; those are the recipient's responsibility and are not included in our prices.
Delivery time: typically 10 to 15 business days in the US and 10 to 20 business days internationally. The tracking number is emailed the moment the order ships.
Full shipping policy.
Refunds and returns
See our full refund policy for details.
New and factory-sealed
New and factory-sealed. Every pen, cartridge, case and cooler we sell ships new in sealed packaging.
Questions before you order? Email hello@preppinpeppers.com.
Laboratory reconstitution hardware, sold for research use only. Not for human or veterinary use.
