
Stanley Classic 25oz Bottle
Price: £36.99
Weight: 595g
Best for: General outdoor use
Key attributes: Excellent performance, robust and durable, integrated cup
This heavy-duty flask has an effective easy-pour stopper that reduces the chance of spillages. The integrated cup is a good size and has an insulated rim to prevent burnt lips. You can actually get more in the flask than the manufacturer’s stated capacity too – we filled it up to 800ml. It’s a well-made and durable flask with very good heat retention. In fact, this was one of the best performers in our temperature test. The only possible drawback is that the chunky design adds weight and bulk to your pack.
Full Specifications
Capacity: 750ml (25oz) / Temperature test: 0 hrs 90°c, 90 mins 85.2°c, 4 hrs 79.5°c, 6 hrs 75.3°c, 8 hrs 71.4°c, 24 hrs 48.4°c / Made from 18/8 stainless steel / Leak-proof / Insulated lid doubles as a cup / Dishwasher safe / Lifetime warranty.
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Sho Original 2.0 Bottle
Price: £24.99
Weight: 483g
Best for: General outdoor and everyday use
Key attributes: Excellent performance, good value, versatile
Another good-looking flask with a hard-wearing, textured, non-slip finish. The design prevents condensation from forming on the outside of the flask and ensures it stays cool to the touch. We particularly liked the useful carabiner accessory (sold separately, £3.99), for attaching the flask to a pack. It punched above its weight in our temperature test, being beaten only by the Thermos Ultimate Series 500ml and the two larger capacity flasks from Sigg and Klean Kanteen. All in all, it’s a versatile option for a multitude of everyday and outdoor uses. The only design drawback is the flask’s narrow neck and mouth, which minimises heat loss but makes cleaning a little tricky.
Full Specifications
Capacity: 750ml (25.4oz) / Temperature test: 0 hrs 90°c, 90 mins 87.2°c, 4 hrs 81.8°c, 6 hrs 78°c, 8 hrs 74.1°c, 24 hrs 50.6°c / Made from 18/8 Stainless Steel / Lifetime guarantee / BPA Free and EU safety tested / Over 10% SHO profits donated to charity.

Outwell Wilbur Vacuum Flask M
Price: £17.99
Weight: 489g
Best for: General outdoor and everyday use
Key attributes: Great value, integrated cup
This flask has a familiar design with a classic ‘pop’ stopper that makes for easy pouring. With cheap, inferior flasks these are often prone to leaking but with this Outwell version the component seems well-made and reliable. It certainly didn’t leak on test. It’s a simple, inexpensive flask that makes use of a classic tried and tested design. The wide mouth makes the flask easy to fill and clean, while the cup’s plastic liner ensures you won’t burn your mouth. On the other hand, it is fairly bulky for a 750ml flask, with a small cup compared to some other designs. The external finish is also a bit slippery and prone to scratching.
Full Specifications
Capacity: 750ml (25oz) / Temperature test: 0 hrs 90°c, 90 mins 83.6°c, 4 hrs 74.4°c, 6 hrs 68.2°c, 8 hrs 62.5°c, 24 hrs 33.6°c / Made from stainless steel / Easy to open and close / Integrated lid functions as a cup / Odour and taste free.

GSI Glacier Stainless Microlight 720
Price: £39.95
Weight: 306g
Best for: Lightweight hiking and backpacking
Key attributes: Very light, design enables one-handed drinking, wide mouth for easy filling and cleaning.
Designed for gram-counting backpackers, this is an extremely lightweight flask with double walls that are 60% thinner than standard vacuum flasks. The design is neat and compact, but also incorporates a locking, flip-top cap for one-handed drinking. A non-slip silicone pad helps to prevent accidental damage to the base of the flask. It is an impressively light and versatile design. The wide mouth makes for easy filling and cleaning, while the ergonomic spout is easy to drink from. You do need to treat this flask with care, as the stainless steel outer wall is very thin and will dent more easily than others. The smooth finish is also easily marked and scratched – though perhaps that just adds character?
Full Specifications
Capacity: 720ml (24oz) / Temperature test: 0 hrs 90°c, 90 mins 83.7°c, 4 hrs 75°c, 6 hrs 69.1°c, 8 hrs 63.4°c, 24 hrs 35.4°c / 2mm walls result in a compact footprint that fits anywhere / Made from 18/8 stainless steel / Push-button, flip top cap locks closed for transport and locks open for easy drinking.
Hydro Flask Lightweight Trail Series 24oz Wide Mouth
Price: £47.99
Weight: 289g
Best for: Lightweight hiking and backpacking
Key attributes: Very light, stylish finish, grab handle.
This is another impressively lightweight flask with a neat and compact design. The wide mouth makes for easy filling and cleaning, and the silicon grab handle means it is easy to pull this flask from the side pocket of a rucksack. Like the GSI Microlight, the stainless steel outer wall is necessarily thin and will dent more easily than others. Our temperature test found that heat-holding performance wasn’t quite as good as the GSI rival, and nor does it offer one-handed drinking to make life easier on the trail (though it is compatible with the Hydro Flask straw lid, sold separately). On the other hand, it is a few grams lighter than the GSI Microlight 720.
Full Specifications
Capacity: 720ml (24oz) / Temperature test: 0 hrs 90°c, 90 mins 81.1°c, 4 hrs 71.5°c, 6 hrs 63.7°c, 8 hrs 57.7°c, 24 hrs 31.7°c / 25% lighter than standard Hydro Flask 24oz wide mouth bottle / Fits most backcountry hydration filters / Made from 18/8 pro-grade stainless steel / Insulated wide mouth cap / Flexible perforated strap and aluminum pivots for added weight loss / BPA-Free and Phthalate-Free / Dishwasher safe.

Lifeventure TiV 700 Vacuum Flask
Price: £18.99
Weight: 464g
Best for: Hiking and general outdoor use
Key attributes: Versatile, good value.
This vacuum flask incorporates an internal copper coating in its construction for greater heat retention. We liked the solid screw-in stopper and integrated cup, as well as the external powder finish that stays condensation-free and cool to the touch, while being resistant to scratches. It’s a good value flask with solid all-round performance, finishing a respectable sixth overall in our temperature test. It’s relatively lightweight and the slim design slips easily into a pack. Despite the ‘pouring spout’, we noted that pouring can be a bit slow and splashy if you don’t completely remove the stopper. The mouth of the flask is also quite narrow, while the integrated cup is quite small.
Full Specifications
Capacity: 700ml (24oz) / Temperature test: 0 hrs 90°c, 90 mins 85.7°c, 4 hrs 79.5°c, 6 hrs 74.8°c, 8 hrs 70.5°c, 24 hrs 44.6°c / Stainless steel construction with copper coated inner wall / Screw in stopper / Lid can be used as a cup.

MontiiCo Original Bottle
Price: £19.95
Weight: 296g
Best for: Everyday and active use – great for the gym!
Key attributes: Versatile, good value.
This attractive flask looks great and incorporates a number of practical design features, including a grippy, scratch-resistant powder-coated finish and a plastic-free stopper with an eco-friendly bamboo insert. We also liked the integrated carry handle. It is a lightweight and versatile flask that makes a good general-purpose drinks bottle, while also keeping a brew warm in a pinch. The slim design slides easily into a pack. You can also buy a sports cap to fit this flask, which makes it a great option for active use or taking to the gym. Admittedly, our tests showed that heat retention was not as good as other flasks. The stainless steel outer wall of the flask is very thin and thus likely to dent more easily than others.
Full Specifications
Capacity: 600ml (20.3oz) / Temperature test: 0 hrs 90°c, 90 mins 79.6°c, 4 hrs 66.5°c, 6 hrs 58.3°c, 8 hrs 51.6°c, 24 hrs 22.2°c / Stainless steel construction / Wide mouth opening /
Stylish, eco-friendly bamboo lid / Grab handle / Bottle + packaging 100% recyclable / No plastic comes in contact with your drink (silicone seal only) / BPA-free / Hand wash only.

Camelbak Hot Cap 20oz
Price: £29.99
Weight: 305g
Best for: Your daily coffee hit.
Key attributes: Unusual cap design, leak-proof, lightweight and portable.
This innovative flask has a leak-proof cap with an unusual twist stopper that allows 360° drinking from any angle. It’s ideal for swigging coffee on the go. The wide mouth also makes for easy filling. It’s a lightweight and portable design with a nice powder-coated finish, which makes the flask easy to hold in one hand. Keep it in your commuting bag or in the car for coffee stops. In terms of heat-holding power, be aware that it reaches its limits after about 4 hours. The cap design is also a bit awkward to clean, though you can just stick it in the dishwasher.
Full Specifications
Capacity: 591ml (20oz) / Temperature test: 0 hrs 90°c, 90 mins 79.8°c, 4 hrs 67.2°c, 6 hrs 59.3°c, 8 hrs 53°c, 24 hrs 25.9°c / 360° cap allows drinking from any side of the bottle / Leak-proof rotating valve twists open for easy sipping / Sweat-proof insulation ensures a no-slip grip / Dishwasher safe cap.

S’well Traveler 16oz
Price: £35
Weight: 360g
Best for: Everyday use.
Key attributes: Stylish looks, leak-proof, portable.
When single-use plastics started getting a bad rap, S’well became the drinks bottle of choice for a host of celebrities and ‘influencers’. But they’re not all style over substance – the design consists of a triple-walled construction incorporating a copper layer for improved insulation. This flask is lightweight and practical – the ergonomic shape makes it easy to hold, the really wide mouth makes for easy drinking, filling and cleaning, and the grooved lid makes it easy to open, even if screwed on tightly. It’s sure to draw admiring glances if you leave it on your desk at the office. It’s just a shame that the capacity is a bit small, and it’s relatively expensive for a little flask.
Full Specifications
Capacity: 470ml (16oz) / Temperature test: 0 hrs 90°c, 90 mins 83.9°c, 4 hrs 74.1°c, 6 hrs 67.5°c, 8 hrs 61.8°c, 24 hrs 31.6°c / Wide mouth for stirring coffee or adding ice cubes / Made from 18/8, food-grade stainless steel / Condensation-free exterior / BPA- and BPS-free / Hand-wash only.
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