For all #diabetics, in case you're dependent on insulin and interested in long-haul travel: I stress tested this device in photos (exact model is https://www.amazon.de/dp/B0FJY2LQSH) on my Japan/Korea trip, including flight times of 12-18 hrs (incl. layovers) as an insulin transporting vessel.
The device is a peltier-cooled mini refrigerator, about as big as a standard thermos, maybe a bit slimmer. It runs on 5V/2A usb-c. It keeps the tube inside at desired temperature, down to 4°C. I found that 8°C was a good setting. Doesn't drain power banks too hard and is sufficiently cool. Temperature is pretty constant with ~1°C max variation. It needs fresh air all the time, but it keeps well in decently made bottle holder satchels of hiking backpacks.
Only issue: No battery is attached, so you need a power bank. I use an Anker Power Core that carries 100 Wh. It can continuously power the device for 6-14 hours depending on outside temperature (the hotter it gets outside, the more power it draws). My reference value for 21°C room temp was 14h 8°C cooling. 25°C outside temp and direct sunlight dropped performance time to 8h. As you can see, it's quite sensitive.
Now the issue is that power banks are a dicey subject on planes. Strictly speaking, using and charging them is illegal on most carriers. But: most planes have on-board power outlets you can use to power the thing during flight, unless you're flying low cost carriers. And by power outlets I mean 100V AC power. The USB ports in planes usually don't provide the amps necessary. I also used an Anker Nano travel adapter (this thing is insanely good as well https://www.anker.com/eu-en/products/a9215?variant=55167866601848In) to conveniently charge the fridge via a USB-C cable and also charge other devices like my phone as well. Granted, the device takes half of the workload the charger can provide, but that's still 10 watts you can use, which usually is enough for a phone to charge steadily. With low cost carriers you often either need to use the power bank and not get caught or write to them in advance (at least a week before flight) that you need continuous power either at your seat or have them power it for you (and they can do this afaik). Don't think a doctor's note spontaneously produced at check-in suffices. I almost was thrown off a flight because I tried being transparent about the whole thing (while providing such a doctor's note).
Using the fridge with a power bank, you should adhere to three rules:
1: If you can power it without the power bank, go for it.
2: Whenever you can charge your power bank without substantive jail risk, go for it.
3: Tell people who complain to you regarding airport outlets ("I need to charge, too") to fuck off (that's medicine!). They always can charge their phones on the plane (esp on long-haul).
About the power bank: Please buy a good one (again, Anker Power Core is reliable good tech, but there's other good brands as well). Don't get a cheap model. Those are usually the ones that spontaneously combust.
Where this device shines is long train rides, bus or car travel. You can take lots of stuff with you in it, I traveled with insulin supply for 5 weeks, but your needs might differ from mine. But it should be enough for most vacations. Even with flights, it's so much better than relying on ice or cooling packs.
If you want to give it a try, I suggest you buy one and test it with thermometers and your power bank to see if it fits your use case and needs. If it doesn't, return it.
Smudge The Insult Cat 🐀