The Captain Stag Vacuum Insulated Super Cold Cooler Box is a hard cooler announced on Aug 4, 2026. It puts vacuum insulation panels on 5 sides: front, back, both sides and bottom. In the maker's own test, ice lasted to day 7 in the 45L and day 5 in the 21L. Weight is about 6.1kg for the 45L and about 4.1kg for the 21L.
The Gear Nerd's Pick
Spending more than half the year camping, every trip out to buy more ice is travel effort. So I choose a cooler by how many days the ice lasts before I look at capacity. Vacuum panels pass heat less readily than an air layer, and putting them on 5 sides with urethane wrapping all 6 produces the strongest cold retention Captain Stag makes. For multi-night family camping, the 45L is the pick.
Key points
- Release announced Aug 4, 2026. 45L (UE-112) about 6.1kg, 21L (UE-111) about 4.1kg
- In the maker's own test (ice at about 50% of capacity, room temperature 28±2°C), ice remained to day 7 in the 45L and day 5 in the 21L
- The 45L holds 12 2L bottles and the 21L holds 4. At about 136g per liter, the 45L is the lighter of the two
In this article (8 sections)
When is the Super Cold Cooler Box out? The numbers for the two sizes
Captain Stag announced on Aug 4, 2026 the release of its Vacuum Insulated Super Cold Cooler Box. It comes in 2 sizes, the 21L (UE-111) and the 45L (UE-112), at open pricing.
The answer: it is a cooler for people who want ice to last a long time on camps of 2 nights or more. In the maker's own test, ice lasted to day 7 in the 45L and day 5 in the 21L.
How I judged it
The first thing I looked at was the insulation build. Vacuum insulation panels on 5 sides (front, back, both sides, bottom) and high-density urethane packed into all 6 sides including the lid make a 4-layer wall. Captain Stag claims the strongest cold retention of its own coolers.
What I weighed was weight. The 45L is about 6.1kg, heavier than the soft-leaning coolers that sell on lightness. Still, I recommend it because per liter it is about 136g (6.1 ÷ 45), lighter than the 21L's about 195g (4.1 ÷ 21), and it holds cold 2 days longer. For multi-night family trips, I pick the 45L.
Image: Rakuten Ichiba
Captain Stag Vacuum Insulated Super Cold Cooler Box 45 (UE-112)
Lowest price on Rakuten: JPY 16,578 (as of 10/18). Prices vary by up to JPY 20,670 between shops. Prices change daily.
21L vs 45L, and comparisons with other coolers
Scroll the table sideways →
| Model | Capacity | Weight | Days ice lasted | 2L plastic bottles |
|---|---|---|---|---|
| Super Cold 45 (UE-112) | About 45L | About 6.1kg | Until day 7 | 12 |
| Super Cold 21 (UE-111) | About 21L | About 4.1kg | Until day 5 | 4 |
| LOGOS Slip Lid 40 | About 40L | About 4.2kg | 6 days or more | 9 |
| Coleman Extreme Cooler 52QT | About 49L | About 4.6kg | About 5 days | ― |
From the outer size, the box volume is about 88.0L (58 × 37 × 41cm) for the 45L, so capacity is about 51% of it. The 21L is about 52.2L (46 × 36 × 31.5cm), about 40%. The larger size loses a smaller share to wall thickness.
Weight-and-capacity division for other coolers is laid out in our comparison of 12 coolers. LOGOS's 55L with no zipper on the lid is covered in the Slip Lid 55 review.
Image: Rakuten Ichiba
Captain Stag Vacuum Insulated Super Cold Cooler Box 21 (UE-111)
Lowest price on Rakuten: JPY 15,200 (as of 10/18). Prices change daily.
How the vacuum insulation panels work
A vacuum insulation panel is a board with a glass wool core wrapped in aluminum film and the air pumped out. With almost no air to carry heat, it passes less heat than urethane of the same thickness. In this cooler, only the lid is insulated with urethane instead of a panel.
The 8-hour cold retention rating is 4°C or below for the 45L and 5°C or below for the 21L. This is a JIS-based test: water at 1–4°C filling 80% of capacity, left in a 40±2°C room for 8 hours, then measuring water temperature. It is measured differently from the days test.
Who the Super Cold Cooler Box suits
It suits people who go on multi-night summer trips or to campgrounds far from stores. The 45L takes 12 2L bottles, putting a family's drinks and food into one box. The 21L is a size that also suits a one-night solo or two-person trip, and disaster preparedness.
If you carry it to a site a little way from the car, the 45L at about 6.1kg plus contents is easier with an outdoor wagon.
21L or 45L: which should I pick?
By how much fits, the 21L holds 28 350ml cans and the 45L holds 70. For 500ml bottles it is 24 and 53, so the 45L holds more than double the 21L (53 ÷ 24 is about 2.2 times). The capacity gap is about 2.1 times, so the larger one wastes less of its shape.
For me, 3 or more people or 2 nights or more means the 45L, and a solo or couple's one night means the 21L. The 21L is 31.5cm high, about 9.5cm lower than the 45L, a size that is easy to stack on the upper level of the cargo area.
Things to watch
As a guide for ice packs, use about enough to cover the top inside, 2 of the maker's packs for the 45L and 2–3 for the 21L. The body withstands 80°C and −10°C.
The price is open pricing, so it varies by store. Before buying, check that the size number (UE-111 / UE-112) matches.
FAQ
When is the Super Cold Cooler Box released?
Its release was announced on Aug 4, 2026. The price is open pricing, set by each store.
How do the 21L and 45L differ?
Besides capacity, weight is about 4.1kg versus about 6.1kg, and the days ice lasted in the maker's test are day 5 versus day 7. The 21L holds 4 2L bottles and the 45L holds 12.
Which sides have the vacuum insulation panels?
Five: front, back, both sides and bottom. All 6 sides, including the lid, are also filled with high-density urethane.
