Sierra Designs

Sierra Designs Flex Capacitor™ 25–40L – lightweight hiking pack with hip belt

SKU: KY-2557 Category: Outdoor Gear

Variant: S/M S/M

M/L M/L
Colour: Bearing Blue Bearing Blue

On stock in variations

160,00 €

incl. 19% VAT , Free shipping

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Light like a daypack. Built like a backpacking pack.

The Flex Capacitor™ 25–40L is for those who pack light, but still need structure, stability, and smart features. With its expandable volume, Y-Flex DAC frame, and real hip belt, it bridges the gap between minimal daypacks and full-size hiking packs.

✅ 25–40 L adjustable capacity
Side compression gussets let the pack grow or shrink with your gear.

✅ Stable Y-Flex frame
Carries smooth and close – even with smaller loads.

✅ Smart pocket layout
Stretch side pockets, zippered hipbelt, lid pocket & shoulder stash all within reach.

✅ Ultralight without compromise
At 1.1 kg, it’s among the lightest structured packs in its class.

✅ For weekend trips, bivy nights, or fast overnight missions
If you don’t carry much – but carry it right – this pack was made for you.

Sierra Designs Flex Capacitor™ 25–40L – lightweight hiking pack with hip belt

Description

Productinformation in detail

Key Features

Materials & Care

Size Guide

Reviews

Description

Productinformation in detail

Key Features

Materials & Care

Size Guide

Reviews

Light like a daypack. Built like a backpacking pack.

✅ 25–40 L adjustable capacity
Side compression gussets let the pack grow or shrink with your gear.

✅ Stable Y-Flex frame
Carries smooth and close – even with smaller loads.

✅ Smart pocket layout
Stretch side pockets, zippered hipbelt, lid pocket & shoulder stash all within reach.

✅ Ultralight without compromise
At 1.1 kg, it’s among the lightest structured packs in its class.

✅ For weekend trips, bivy nights, or fast overnight missions
If you don’t carry much – but carry it right – this pack was made for you.

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When you need more than a daypack – but not a full-on trekking pack.

The Flex Capacitor™ 25–40L is made for hikers who move light, but know that minimal gear still deserves real structure.
It offers enough volume for bivy nights, weekend tours, or long day hikes – with a suspension that keeps everything stable and close, even when packed small.

Compact, but expandable – thanks to flexible volume

This pack expands from 25 to 40 liters using integrated side gussets with a simple tension strap system.
There’s no need for zip-ons, modular extras, or complicated setups.
The volume adjusts to your gear – not the other way around.

Lightweight build – but real suspension

The Y-Flex frame with DAC aluminum support distributes weight evenly between hips and shoulders.
Even with a small load, the pack sits close and stable – no bouncing, no collapse.
It’s light, but it carries like something more substantial.

Access that works on the trail

Everything is where it should be:
Stretch mesh side pockets, zippered hipbelt, U-zip lid entry, and shoulder stash pockets.
Nothing flashy – just thoughtful access points that make sense outdoors.

Our take – Flex Capacitor™ 25–40L at Campanions

This pack is built for hikers who carry less – but care about how they carry it.
It’s not a fastpack, and it’s not a stripped-down sack. It’s a well-structured, lightweight tour pack for short to mid-range adventures, where comfort still matters.
If you move smart and pack light, this is the pack that’ll keep up.

Item information	Value
Color:	blue

✅ 25–40 L adjustable volume
Side compression gussets adapt to your gear without added parts.

✅ Stable Y-Flex suspension system
The DAC frame delivers structure and control – even with smaller loads.

✅ U-zip top entry and smart outer pockets
Quick access without taking off your pack.

✅ Only 1.1 kg – with full support and features
Ultralight but built with a real hip belt, frame, and trail access.

✅ Perfect for bivy nights, weekend hikes, and long day missions
Made for light packers who still care about carry comfort.

Materials:
The pack is made from 100D nylon-poly ripstop and 420D Oxford nylon – lightweight but abrasion-resistant. A DAC aluminum frame provides structure and load control without adding unnecessary weight.

Care:
After your trip, wipe the pack with a soft cloth and lukewarm water. Do not use detergents or put it in the washing machine.
Let it air dry fully in an open, upright position – keep it away from heaters and don’t fold it tightly.

Which size fits you best?

Manufacturer Specs (S/M and M/L)

Torso fit: 16″–19″ (41–48 cm)
Hip belt S/M: 29″–32″ (73–81 cm)
Hip belt M/L: 32″–35″ (81–89 cm)
Weight S/M: 2 lbs 7 oz (1.10 kg)
Weight M/L: 2 lbs 8 oz (1.13 kg)
Dimensions (H × W × D): 23″ × 11″ × 8.5″ (58 × 28 × 22 cm)
Suspension: DAC Y-Flex aluminum frame

Best for you if …

your torso length is between 16″ and 19″ (41–48 cm)
you're about 5'7″ to 6'1″ (170–185 cm) with an average to slim build
you usually carry 13–26 lbs (6–12 kg) of gear on day hikes or overnight trips
you want a lightweight pack with a real suspension system and hip support

✅ This model fits rather compact – if you're in between sizes, we recommend going with M/L, provided your hip measurement allows for it.

Not ideal if …

you're under 5'5″ (165 cm) or have a short torso (<16″)
→ The hipbelt may sit too low and the frame won’t match your back length
your torso is longer than 19″ (48 cm)
→ The pack will feel too short and can become uncomfortable over time

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