HydraPak
HydraPak Flux 1.5 L Flexible Bottle
- Weight for its size: 9/10 How much it adds to your pack for the water it holds.
- Packed size (empty): 8/10 How much room it takes up when it is empty, for the water it holds.
Lowest price we found
£27.99 at Ultralight Outdoor Gear
Go to Ultralight Outdoor Gear Compare 3 shopsCamp water carrying: 1.5 L in a bottle that rolls up when empty
- Type
- Soft
- Capacity
- 1.5 L
- Weight
- 122 g
- Packed
- Not published
Where to buy
Ultralight Outdoor Gear £27.99 In stock. Free delivery. Shop shows RRP £29.99. Free tracked UK delivery on all orders (header: free over £15).
View at shop: Ultralight Outdoor GearSportsshoes £29.99 In stock. Delivery £4.99. Standard+ 48 UK delivery £4.99 on its page. Its site-wide discount code is not included in the price.
View at shop: SportsshoesHydraPak £30 In stock. Delivery £3.60. Mammoth colour in stock; Sage Green is out of stock. HydraPak's UK shop. Free UK delivery over £50 (its shipping policy page says £75); below that £3.60 Royal Mail Tracked 48 or £6.00 DPD next day.
View at shop: HydraPakPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Weight for its size
From maker's figures 9/10How much it adds to your pack for the water it holds. 9: Among the best you can buy for this.
HydraPak lists 122 g for 1.5 L (its UK and US pages agree): 81 g per litre, under 100 g/L. Ultralight Outdoor Gear lists 120 g, the same band; Sportsshoes lists 122 g.
Packed size (empty)
Estimate from maker's specs: soft bottle: rolls up when empty 8/10How much room it takes up when it is empty, for the water it holds. 8: Clearly better than most.
Estimate from maker's specs
In short
Good for
- Camp water carrying: 1.5 L in a bottle that rolls up when empty
- Dirty-water bottle for a squeeze or screw-on filter with a 42 mm thread (HydraPak Filter Cap, Katadyn BeFree)
- Long-distance trips where one big bottle replaces a heavier rigid one
Strengths
- 122 g for 1.5 L, about 81 g per litre
- Shaped like a hard bottle and stands upright when full
- Rolls up to pocket size when empty and stows in its bail handle
- Dust cover protects the twist-to-drink nozzle
- Fits most 42 mm filters, including HydraPak's own filter cap and the Katadyn BeFree
- Beyond Lifetime Guarantee on defects
Weaknesses
- Some buyers on HydraPak's site report a plastic taste that stays after washing
- Some find the twist cap hard to open when it is cold or wet
- A few buyers raise concerns about durability under pressure or impact
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.