Sea to Summit Trek Sleeping Bag Womens TK1 Long

20% OFF

Original price was: $399.00.Current price is: $319.20. inc GST.

Incorporating our 2D PermaShell™ fabric and a premium 650+ Loft ULTRA-DRY Down™, the Sea to Summit Trek sleeping bags are a refined classic.

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The 60/40 fill ratio in the Trek bags is maintained using a side block baffle and differential cut shell. In the top of the shell a 3D side wall—a feature normally reserved for technical alpine sleeping bags—provides more space for the down to loft right to the edge of the bag.

An oversized security pocket located inside the Trek Sleeping Bag is easily accessible, ideal for stashing passports and other valuables while travelling. The soft touch lining fabric is down-proof by construction and highly breathable offering a comfortable sleep.

The Trek series is our choice for adventure travel and globetrotting. Whether sleeping in hostels throughout Europe, backpacking South America or discovering the Stirling Ranges in Western Australia.

The tapered rectangular design offers a good compromise between the comfort of a generous cut shape and the warmth of a closer fit. A full length side and foot zip allow the Trek series to be opened out into a full quilt for use indoors and warm weather.

The women’s Trek also features two combined down and THERMOLITE® baffles under the foot area, to help keep heels and ankles warmer where feet compresses the down.


  • Tapered rectangular shape
  • 2D Permashell DWR shell
  • ULTRA-DRY Down™ 650+ Loft – 85/15 Premium Duck Down
  • Differential cut shell with 3D side walls, sideblock baffles with 60/40 fill ratio combined with side block baffles
  • Zip draft tube with anti-snag as well as cushioned hood with internal drawcord
  • 2 way YKK#5 zips with separate foot zip and large internal zippered pocket
  • Includes light weight Ultra-Sil® compression bag and storage cell/laundry bag
  • Women’s models include two combined down and THERMOLITE® baffles under the foot area, to help keep heels and ankles warmer where down is compressed

Sea to Summit Trek Sleeping Bag Temperature Range:

Size/Variation: TK1 TK2 TK3 Women’s TK1 Women’s TK2
Comfort °C 5 -1 -5 -2 -8
Lower Limit °C 0 -8 -11 -8 -15
Extreme °C -15 -25 -30 -26 -36
Season Rating: 3 3 4 3 4


Sea to Summit Trek TK1 Sleeping Bag Size/Fill Weight:

Size/Variation: Regular Regular Wide Long Women’s Regular Women’s Long
Width (Shoulders): ø 152cm ø 172cm ø 162cm ø 151cm ø 150cm
Recommended User Height: <183cm <183cm <192cm <165cm <179cm
Fill Weight: 350g 450g 400g 500g 550g
Total Weight: 790g 950g 880g 990g 1080g
Compressed Volume: 5.1L 6.0L
Zip Location: Left Left Left Right Right

Sea to Summit Trek TK2 Sleeping Bag Size/Fill Weight:

Size/Variation: Short Regular Regular Wide Long Women’s Regular Women’s Long
Width (Shoulders): ø 151cm ø 152cm ø 172cm ø 162cm ø 148cm ø 150cm
Recommended User Height: <165cm <183cm <183cm <192cm <170cm <179cm
Fill Weight: 500g 500g 600g 550g 700g 750g
Total Weight: 940g 980g 1160g 1090g 1210g 1300g
Compressed Volume: 6.0L 7.0L
Zip Location: Right Left Left Left Right Right

Sea to Summit Trek TK3 Sleeping Bag Size/Fill Weight:

Size/Variation: Short Regular Long Women’s Regular Women’s Long
Width (Shoulders): ø 151cm ø 152cm ø 162cm ø 148cm ø 150cm
Recommended User Height: <165cm <183cm <192cm <170cm <179cm
Fill Weight: 700g 700g 750g 700g 750g
Total Weight: 1150g 1190g 1300g 1210g 1300g
Compressed Volume: 7.05L 7.0L
Zip Location: Right Left Left Right Right

Technical Features:


EN13537 is a European standard for sleeping bag temperature ratings.

Everyone sleeps differently; some people are very warm sleepers while others feel the cold easily. There are many factors that affect your warmth and comfort in a sleeping bag. An important factor is that you use a good insulating mat to prevent your body heat from being drawn into the cold ground. Other factors include your tent or shelter, gender and metabolism, clothing, sleeping bag liner, use of the hood and your daily calorie intake.

Although the EN13537 standard does not identify a single precise temperature a tested sleeping bag is suitable for, it does provide an industry standardised temperature range that a typical user can refer to as a guide for the conditions their bag will be most comfortable in.

The EN13537 standard provides three temperature levels to guide a consumer in their choice:

Comfort: The temperature at which a standard woman can expect to sleep comfortably in a relaxed position. If you consider yourself a cold sleeper use this rating to decide the coldest temperature the sleeping bag is suitable for.

Lower Limit: The temperature at which a standard man can sleep for eight hours in a curled position without waking. If you consider yourself a warm sleeper you can use this rating to decide the coldest temperature the sleeping bag is suitable for.

Extreme: This is a survival only rating for a standard woman. Between the lower limit and the extreme rating a strong sensation of cold has to be expected and there is a risk of health damage due to hypothermia. This is an extreme survival rating only, we do not recommend you rely on this rating for general use.

The EN13537 temperature tests use a thermal manikin with heaters and temperature sensors to measure the insulation value of a sleeping bag. This manikin is wearing one layer of long underwear and is placed inside the sleeping bag on an insulating mat. The test is conducted in a temperature controlled chamber and a range of comfort temperatures are derived from measuring the energy required to maintain homeostasis in the manikin
to a set temperature.

All Sea to Summit sleeping bags have been tested to the EN13537 standard. We recommend you use our EN13537 quoted ratings as a guide and a comparative reference to other EN13537 tested bags.


To achieve maximum loft and insulation, down must be dry and uncompressed. Even if sleeping in a dry tent your sleeping bag can still get damp or wet from condensation; vapour leaving your body passes through the down, and condenses on the outside and inside of your sleeping bag shell. The condensation that forms on the inside of the shell is absorbed by the down reducing its loft and warmth.

Over several days of packing and unpacking a sleeping bag, wet down mixes with dry down affecting its ability to loft. By the end of a long trip it is not uncommon for a sleeping bag to have decreased in warmth significantly because the down is damp, reducing its loft and its ability to insulate properly.

At Sea to Summit we have solved this problem with our 3D NanoShell® and ULTRA-DRY Down®.

The NanoShell® Face is a 20 denier fabric that is highly breathable, water resistant and treated with a Nano DWR for unparalleled performance in wet and windy conditions .

The 3D Barrier is a non-woven silicone encapsulated 3-dimensional layer under the NanoShell® Face.

Together they form the 3D NanoShell®, a condensation management system that insulates, repels water and protects loft.

The 3D NanoShell® provides a 3-dimensional layer between the cold external environment and the warm down inside your sleeping bag. When vapour passes through the down, it enters the 3D Barrier, before exiting the breathable NanoShell® Face fabric.

Any condensation that forms under the NanoShell® Face fabric is separated from the down by the 3D Barrier. Due to its hydrophobic nature, this 3D Barrier traps the condensation preventing this moisture from mixing with the down layer .

When conditions become favourable the 3D Barrier also promotes fast evaporation expelling moisture to the outside preserving dry and fully lofted down .

Over several days of usage, the weight of absorbed moisture and the associated drop in insulation that other bags would suffer makes 3D NanoShell® the wise choice for expeditions.


2D PermaShell® fabric is a high density weave 30 denier Nylon with a DWR finish. This material is highly vapour permeable and down proof by construction.


Down insulates best when it is uncompressed and fully lofted. To help the down loft correctly we use a differential cut shell and lining. The top shell of all Sea to Summit sleeping bags is cut larger than the lining. This creates space in between for the down to loft fully. In the bottom of the bag we use a reverse differential cut. By increasing the size of the lining relative to the shell, down lofts up to fill the voids around your body, torso, legs and the small of your back. Trapping heat close to the skin is essential for efficient warm sleeping.


Down is the soft plumage of birds that lives under the feathers. A single piece of down is called a plume. The majority of down used in clothing and bedding comes from geese and ducks. Down is one of the best warmth to weight insulators available. It is not only warmer for weight, but compresses much smaller and is much more durable than most synthetic fill equivalents.

Loft is the volume for a given weight of down. High loft down is warmer for a given weight than low loft down. The most common measure of loft is fill power, a term which is often used interchangeably with loft. Fill power is the volume, in cubic inches, that an ounce of down will fill. Thus, one ounce of 650 loft down will fill 650in3.

Composition refers to the percentage of down versus feathers in a batch of down. In Australian and US regulation, 90/10 means that 90% of the batch is down plumes, the other 10% is small feathers. The higher this ratio, the lighter, softer and more compressible a sleeping bag will be. It also means there are fewer feather quills or spines to poke through the stitching or fabric of a bag.


Sea to Summit Sleeping bags use down that has been sourced and certified by the Responsible Down Standard (RDS). The RDS is helping to shift the entire down and feather industry towards more humane animal rearing and handling practices. Overseen by the industry leading Textile Exchange, the RDS requires independent, third party assessments of all aspects of animal rearing and handling throughout the entire supply chain. By only using down that meets the audited requirements of the RDS we can have confidence that each phase of the collection process has been completed with the welfare and ethical treatment of waterfowl in mind. To find out more information about how the RDS is improving animal welfare during down collection, please visit


  • Repels moisture
  • Retains loft
  • Dries faster
  • Anti-bacterial and anti-microbial
  • Prolongs the life of your sleeping bag

ULTRA-DRY Down® is a permanent* Nano-level water repellent polymer treatment applied to our high loft, high quality down. The Nano-thin treatment vastly improves our down’s reaction to water without effecting its weight or loft performance. ULTRA-DRY Down® retains over 60% more loft and absorbs 30% less moisture when compared with untreated down. Sea to Summit sleeping bags dry out 60% faster than bags with untreated down.

The Nano-level treatment also inhibits bacterial and microbial growth, which makes Sea to Summit sleeping bags more hygienic and improves their lifespan.

*No loss of treatment effect has been seen in over 14 wash cycles.

Additional information

Weight N/A
Dimensions N/A

TK3, Women's TK1, Women's TK2


Short, Regular, Long


Sea to Summit

Sea to Summit is an innovative design and product development company that engineers a wide range of intuitively simple products that help make time in the outdoors fun, efficient and comfortable. From our West Australian base, Sea to Summit has grown into an award-winning global brand sold in more than 60 countries. Significant growth and international recognition has strengthened our original ethos ‘to equip and inspire’ and it continues to drive our research and development of the best materials and production methods. It inspires new product innovations that keep us at the forefront of bringing lighter, better made, better performing gear to outdoor enthusiasts around the world.


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