HydraPak
HydraPak PackFlask 750 ml Harness-Mounted Flask
- Weight for its size: 8/10 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
£41.99 at Ultralight Outdoor Gear
Go to Ultralight Outdoor Gear Compare 2 shopsFast day walks and long treks where water should sit on the shoulder strap, within reach
- Type
- Soft
- Capacity
- 0.75 L
- Weight
- 93 g
- Packed
- Not published
Where to buy
Ultralight Outdoor Gear £41.99 In stock. Free delivery. Shop shows RRP £44.99. Free tracked UK delivery on all orders (header: free over £15).
View at shop: Ultralight Outdoor GearHydraPak £45 In stock. Delivery £3.60. Golden Yellow and Sage Green both in stock. HydraPak's UK shop. Free UK delivery over £50 on its shipping page (£75 on its shipping policy page); under that it is £3.60 by Royal Mail Tracked 48 or £6.00 by 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 8/10How much it adds to your pack for the water it holds. 8: Clearly better than most.
HydraPak lists 93 g for 0.75 L (UK and US pages agree): 124 g per litre, in the 100–179 g/L band. Ultralight Outdoor Gear lists 100 g and says it is for the bottle and mesh pouch together (133 g per litre), the same band. HydraPak's material list includes the stretch mesh pouch, so its 93 g appears to cover both, but its page does not say so.
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
- Fast day walks and long treks where water should sit on the shoulder strap, within reach
- Hands-free drinking without taking the rucksack off
- Making a packable squeeze filter system with a 42 mm filter
Strengths
- 93 g for 0.75 L, about 124 g per litre (appears to include the mesh pouch)
- Stretch mesh pouch clips to the rucksack harness; it also carries a phone, snacks or a map without the flask
- Self-sealing silicone nozzle with a dust cover that flips open one-handed
- Collapses when empty
- Takes most 42 mm threaded filters
- Beyond Lifetime Guarantee on defects
Weaknesses
- Holds 750 ml
- The mesh pouch carries a phone, snacks or map only when the flask is taken out
- Hands-free drinking depends on the stretch mesh pouch clipping to your pack harness
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.