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Osprey Womens Sirrus 36 Black

Osprey Womens Sirrus 36 Black

£82.00 £140.00
41% off

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Other colours available:
Osprey Womens Sirrus 36 Ruska Purple
Osprey Womens Sirrus 36 Black
Osprey Womens Sirrus 36 Summit Blue

The women's specific Sirrus 36 is all about ventilation and comfort, featuring an AirSpeed trampoline mesh back panel and Spacermesh shoulder straps and hip belt. Carrying this comfortable pack will literally be a breeze!


Season : 2020S C OFFER

Code : 542611BLK.WS/WM

Weight : 0KG

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What is the Sirrus 36

The Sirrus 36 is all about breathable comfort for long days hiking out in the hills with enough room for spare clothing, food and the essential kit. It is the perfect for pack for any kind of walking or travel and thanks to the fully adjustable AirSpeed ventilated back system; carrying this pack will literally, be a breeze.

What is it made from?

The Osprey Sirrus 36 is definitely built to last and uses tough, durable nylon fabrics to ensure it can soak up the bumps and scrapes of an active life. The main bulk of the bag is made from a super tough 210D Nylon Crosshatch with a durable water-repellent finish to keep your kit dry during light rain (a rain-cover is included for heavy downpours). This fabric is reassuringly thick, yet light enough that you barely realise you're wearing the pack, even when fully laden. Heavier and more durable 420D fabric is used on high wear areas such as the base and sides of the pack.

What are the features?

Designed specifically to fit the female form the unique suspended mesh located on the shoulders, backpanel, lumbar and hipbelt contour and adapt to a wide variety of body shapes and sizes, basically creating a custom fit. Overall the women’s pack shape is narrower and deeper which allows for a greater freedom of movement and increases stability by lowering the position of the load to better suit a woman's natural centre of gravity.  The shoulder harness is designed with different curves to create an anatomical fit for a woman's neck, shoulders and chest. Women's hips are conically shaped with a larger difference between the waist and hip measurements, so the hipbelt is shaped and angled to accommodate this difference, creating comfortable load transfer and increased support.

The main entry point is through a traditional double-clip lid opening to give easy access to the pack’s contents. This style of opening arguably affords better weather protection and improved compression of the load.  In addition to the classic top loader opening, there’s a vertical side zip that enables you to access the contents without having to undo the top. This is really useful if you want to get at something at the bottom of your pack.

The main compartment can also be split in two using the built-in divider and toggles. This creates a separate base compartment for wet or dirty kit, or to simply organise your pack more effectively. This base compartment can also be accessed via a large zipped entrance at the bottom of the pack.

Inside the main compartment is a hydration sleeve with a little clip to stop the bladder from drooping down to the bottom of the sleeve. This is the perfect place to pop your Osprey Hydraulics reservoir.

Osprey equip the Sirrus 36 with a single walking axe loop and the unique “Stow-on-the-go” trekking pole attachment system is a revelation. This allows you to safely stash your trekking poles away when they are no longer required without having to remove the pack or pester a mate to do it for you.

Two side “InsideOut” compression straps pull the weight closer to your back, increasing comfort and carrying efficiency; they also stop gear from rolling about in a half full pack. So called because they can either be used inside, or outside the side pockets. Under the pocket they compress the pack and not the pocket, and over the pocket they secure the contents of the pocket and compress the pack. Simply thread the straps in the manner that suits your needs. Two further straps at base of the pack can be used for storing sleep mats or extra clothing; or can be completely removed if you just don’t need them.

Starting from the top, pockets wise, you get a zipped top lid pocket for quick access to kit that you need to get to easily, such as snacks and navigation equipment. Under the lid is a mesh pocket with an internal key clip, this is perfect for stuff you want to keep separated for safety and security.

The two mesh side pockets will easily take an insulating layer or a 1L bottle and feature a tougher fabric at the base to stop the mesh from being damaged by abrasion. There are two 3D zipped pockets on the hip belt that you can still gain access to even when the hip-belt is done up tight.

On the front of the pack is a large stash pocket, the perfect place to store soggy waterproof clothing or even a wet flysheet. On the outside of the stash pocket is another large zipped pocket, giving you oodles of extra space.

Right down at the bottom of the pack is a small zipped pocket containing the rain-cover. This cover is tethered to stop it flying away in the wind, or it can be completely removed to shed a bit of weight in good weather. The cover fits snugly over the front of the pack and is held firm with an elastic drawcord.

What is the back-system?

This is where the magic happens! Osprey have taken inspiration from their brilliant AntiGravity technology to create a seamless construction across the back-panel and hip-belt using highly breathable suspended mesh to create the AirSpeed Ventilated Trampoline Suspended back system. The whole system is made up of 4 main components:

1. AIRSPEED SUSPENSION – LightWire alloy frame creates low profile air space, optimising pack balance and ventilation. Effectively transfers weight from shoulders to the hips.

2. AIRSPEED SUSPENSION BACKPANEL - 3D-tensioned breathable mesh backpanel ensures supportive fit and enhances airflow and ventilation.

3. SPACERMESH SHOULDER HARNESS - Sewn-in Spacermesh made up of mesh-covered ventilated die-cut foam to enhance all that ventilation and comfort. The shoulder harness is designed with multiple torso size options and features Velcro adjustability.

4. SPACERMESH SEWN-IN HIPBELT – Featuring zippered stretch mesh hipbelt pockets and ErgoPull (forward pull straps) hipbelt closure. The hipbelt connects directly to backpanel mesh to eliminate seams creating a smooth and comfortable lumbar to hipbelt body wrap.

This seamless and continuous construction method transfers weight superbly and is incredibly comfortable and lightweight. The whole pack is suspended away from the back-panel to produce an air gap that allows superb ventilation even on the hottest days. It won’t stop you sweating, but it will make you feel more comfortable.

The Osprey Sirrus packs are one-size only, which keeps thigs simple, but they do have an adjustable Velcro pad on the shoulder harness that can be easily set to various heights depending on the user. Please remember that your torso length and not your height will determine the back length. For more advice on pack fitting have a look at our video below.

Underpinning all that comfortable, breathable AirSpeed mesh is a flexible wire frame to transfer weight to the hips and to provide stability. The frame allows a degree of flex to the pack, so when you’re striding out, your shoulders can move independently of your hips.


The Sirrus 36 features plenty of space for those who are heading into the hills for long days with all the essential kit. This pack also makes the perfect travel and companion, keeping you comfortable and well ventilated in sunnier climes.

  • Adjustable AirSpeed ventilated trampoline suspended mesh backpanel
  • Adjustable torso length
  • Base zip entry
  • Integrated & detachable raincover
  • Internal hydration sleeve
  • Internal key attachment clip
  • Removable sleeping pad straps
  • Side compression straps
  • Single ice axe loop
  • Single vertical zippered side access point
  • Sternum strap with emergency whistle
  • Stow-on-the-Go trekking pole attachment
  • Top lid access
  • Twin zippered hip belt pockets
  • Under lid zipped mesh pocket
Care & Advice

Getting the correct fit for your rucksack is as important as getting the fit right for your boots. A badly fitting pack can inflict misery and discomfort and completely ruin your adventure. This guide is designed to help you get the best fit and comfort from your chosen pack so that carrying all your kit becomes a pleasure and not a chore.


If the pack has an adjustable back length, adjust this to your correct level. Your back length is not related to your height but your torso length. Many packs, and specifically the bigger and more technical packs are available in different back lengths or feature adjustable back systems. Contrary to popular belief, your torso length and not your overall height is the key to getting a well fitted pack. Tall people don’t necessarily have long torsos, just as shorter people don’t always have a short torso length.

Your torso length can be found by measuring from your C7 vertebra (the bony protrusion at the back of your neck when looking down) to the height of your iliac crest (top of your hip bones, where you put your hands on your hips). This measurement will give you an idea of which pack back length to choose.

Once you've got the back length sorted, either by selecting the correct size pack or adjusting the back system, you can begin to follow these simple steps to help achieve a comfortable carry.


Before you start fitting the pack, loosen off all the straps as this will make it easier to get the correct tension later.


Fasten the backpack hipbelt, the general position is the same as where you’d put your ‘hands on hips’ This area is called the pelvic girdle, and what you can feel when you rest your hand on the area is the bony protuberance, the iliac crest. The iliac crest can support the weight from a pack comfortably, and for sustained periods. The padded section of the hipbelt should encompass this and fit securely.

Tighten the straps so the hipbelt feels secure and held firmly around your body. Ensure that the lumbar pad is centered to your lower back to give you maximum support. Remember that your hips carry most of the weight of the pack, so this should be firm but comfortable.


Next, adjust the shoulder straps, pull them until they start to become snug, but ensure that they are not too tight as to lift the pack off your hips. Remember tightening them will stabilise the pack but will increase pressure over the shoulders. If the back length of the pack is correct the shoulder straps will be flush to your shoulders whilst the hipbelt sits in place comfortably. The point where the shoulder straps attach to the main body of the pack should be roughly half way down your shoulder blades; this ensures  that the shoulder straps rolls evenly over the top of your shoulders to distribute the weight correctly.


Fasten the chest strap and pull until taut but not tight, the elastic section should not be extended. This helps keep the shoulder straps from catching in your shoulder joints and keeps the stability of the pack when moving over rough ground.


Top tensioner straps link the shoulder straps to the top of the pack. When tightened, their main function is to stabilise the top part of the pack. The optimum angle for these straps in 45º, but they will stabilise the load even when horizontal or at a more obtuse angle. Tighten them until you feel the top part of the pack rest against your pack, over tightening them will create excessive pressure on the front of your shoulders.


Side tension straps are linked to the hipbelt. By tightening these straps you can stabilise the load but reduce the hipbelt flexibility. Where balance is critical tightening them can help you feel more secure. However, if you are striding out over easy terrain it’s better to loosen these straps to allow full hip flexibility.


Side compression straps come next, pulling these tight does two things: firstly, it stabilises the load, secondly it can lift the lower part of the pack, repositioning the load closer to your back.


Following these steps should give you a comfortable but secure fit on your pack. Sometimes adjustments will need to be made on the go depending on the terrain or the load you are carrying. The perfect fit is very much a personal preference so experiment with different tensions on the pack to find what suits you best.

Technical Information

Fabrics: 210D Nylon Crosshatch/420HD Nylon Packcloth

Capacity (WS/WM) - 36 Litres

Weight (WS/WM) – 1.45kg

Load Range – 7-13kg

Dimensions (cm’s) – 66h x 31w x 31d

Sizing Information

Back length (WS/WM) – 41 - 51cm

  • 4

    Reviewed by Clare ,  On 11/06/2017 14:12:24

    Comfortable sack. Wore it for a week hiking in the Carpathian Mountains; no rubbing, no sore patches so excellent. 4 stars because the straps tended to slip so needed regular tightening.
    YES Clare would recommend this item
  • 5

    Reviewed by del,  On 15/05/2018 00:58:09

    I spent absolutely hours if not months reviewing backpacking gear for my partner and myself, personally i bought the atmos 65 for myself and my partner loves the colour purple and osprey came the top of my list. After hours of checking out their gear, this is no exception and the price trekitt was selling it was a no brainier, this is quality item and stows away the thermarest hd down sleeping back just perfectly in the bottom and expands way more than youd think when packing, she finds it super comfy and balanced to hike with when we are out on dartmoor camping, can highly recomend for one nighters, beyond that we tend to just go out for one night but sure it would be suitable for longer treks if both sharing the load
    YES del would recommend this item
  • 5

    Reviewed by Mand,  On 20/04/2018 10:48:34

    I bought this for two week hike on the Camino Portugues and found it to be a really useful piece of kit. It was the first time I bought a womans ruck sack and was unsure whether this was just marketing hype, but actually found it fit really nicely, (much better than others Ive had), and the waist and chest straps ensure the weight is well distributed and easy to carry. Numerous helpful compartments, robust zips, integral rain cover, and easily accessible loops to stash walking sticks without removing back pack made this a really user-friendly, functional ruck sack.
    YES Mand would recommend this item
  • 5

    Reviewed by Louise,  On 09/08/2018 10:16:28

    The bag is the perfect fit for a female, sits comfortably on the hips and across the chest. I ordered the S/M and Im 5ft 6. It has multiple zips and storage facilities, and a great design where you can get to the main compartment from the top or the bottom of the bag so you dont need to pull everything out. The rain cover is great if you are caught out in unexpected weather. All round good bag, Im taking mine to everest Base Camp Im October.
    YES Louise would recommend this item
  • 5

    Reviewed by Stephanie,  On 21/06/2018 14:58:30

    Really love this rucksack. Great fit; useful features. Really happy with it!
    YES Stephanie would recommend this item
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    Excellent customer service. Really detailed easy to understand product descriptions on the Trekitt website, and gear reviews on the Trekitt YouTube channel made it so easy to choose the right backpack for me.
    Emily - May 2020
    Amazing service! Very helpful in regards sizing and what most matched my needs, despite this being done over the internet. YouTube videos of products being examined are very useful also. Would definitely use again, very fast and efficient delivery. Brilliant! Highly recommended!
    David R - April 2020
    Highly recommend. I usually go to the shop in Hereford as staff are alwasy very helpful and knowledgeable. So this was the first time I have purchased online and the service was just as good as the shop.
    Grizzy - April 2020


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