In 2016 I reviewed the Hydro Flask 21oz, and I loved it so much it became my favourite drinks bottle (read it here), but at the time the cap had a fixed shape that wasn't the best if you wanted to carry it using fingers. When I took it to the gym I tended to carry it by the cap, and my finger would be a bit jammed in, and at an awkward angle.

It was OK for clipping on rucksacks, but because the fixed hole sits directly in the middle it could mean that the bottle sat out at an angle which could be a bit hazardous to people passing by.

Now neither of these 2 things bothered me that much, and I didn't even think it needed to change, until now. Hydro Flask has brought out a new improved cap made with stainless steel pivots and an easy-to-carry strap, and as soon as I saw it thought 'Now this it what my bottle needs'.

I got the new cap, and have been testing it for a few months to see if it is a strong as the old fixed shape, and I am happy to say it has endured all the swinging about that I have done.

It is so much better for carrying, both using your fingers and for attaching to bags and rucksacks, as the loop is much larger, and  it flexes into the correct position.

The Flex cap also has Honeycomb Insulation™ to help keep your drinks cold for up to 24 hours or hot up to 12, and it fits on all the 4 different sizes of the Standard Mouth bottles.

If you have the old style I wholeheartedly recommend investing in this new top. You won't regret it.

Technical Stuff

• Compatible with all Standard Mouth bottles
• Honeycomb insulation™ helps keep your drinks cold for up to 24hrs, or hot up to 12hrs
• Durable, stainless steel pivots allow the strap to move easily
• BPA-Free and Phthalate-Free
• Lifetime Warranty

Website: www.hydroflask.com/en

Where to buy: various online & high street outdoor shops 

Price: from around £8.50