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5.0 1

Sea to Summit

Basecamp Bt4 Sleeping Bag

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You can sleep all through the night even in frosty conditions with the Sea to Summit Basecamp Bt4 Sleeping Bag. This model takes everything you love about the traditional Basecamp sleeping bag range but swaps out down for synthetic which makes it perfect for adventurers who want full features, without the strain on your wallet.  

Insulated with Sea to Summit’s Thermolite fibre, you can be more carefree with this bag, as the synthetic fill makes it easier to clean and take care of. One of the most charmingly versatile sleeping bags on the market, Sea to Summit has added every feature to ensure you can use this bag in all weather conditions.

The clever design lets you adjust the bag to your preferred sleeping arrangement – so you can unzip the side for temperature control, unzip both sides to use it as a quilt with a closed foot box, or you can have your feet hanging out while staying completely zipped up. You can also use it with both sides undone like you would at home in your own bed or remove the top for very warm evenings. If you’re travelling light, just take the top part with you as the bottom will hook onto your mat and keep it in place all night.

Best of all, this bag has a pillow attachment and quilt loops to secure your whole sleep system together – so you can toss and turn all you like and wake up without a crookneck. For a soundless and comfy sleep no matter what the climate the Basecamp BT4 is the one you can rely on. 

  • Four-season sleeping bag
  • Spacious rectangular design
  • Pillow attachment system
  • Quilt loops
  • Sleeping mat sleeve
  • Versatile adjustment for all weather conditions
  • Cushioned internal hood draw-cord
  • 2-way zip on each side of the bag
  • Includes compression sack
Snowys Code:
Supplier Code:
Comfort Temp. Rating:
-8 °C
Lower Temp. Limit:
-15 °C
Internal Girth:
194 cm Chest | 190 cm Hip | 142 cm Foot
External Dimensions:
195L x 97W x 10H cm
Packed Dimensions:
42L x 23W x 23H cm
Compressed Volume:
14.6 L
30D Nylon Taffeta 345T with DWR
Fill Material:
THERMOLITE® insulation
20D Nylon
Zip Draft Tube:
Neck Draft Tube:
With internal drawcord
YKK #5 on each side plus separate foot zip
2.279 Kg
Suggested Use:
Camping | Hiking
Limited Lifetime

(1 reviews)
5.0 1
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Jul 22 2018

Love this sleeping bag

On my way to Uluru we stopped by Adelaide to visit this online store I buy so much stuff from. I needed a good sleeping bag for the days ahead of us. Originally I wanted to get a Basecamp 2 (down) but they didn’t have any in store and I would have to wait for the next day, but because we were on a tight schedule I opted for the Basecamp 4 synthetic material sleeping bag Jake offered and I’m happy I got it.
The size you see in the photo of the guy holding it is the long version, the regular version is a lot smaller. There was a lot of condensation in our pop-up caravan the second night because I didn’t put the outside covers on and water was dripping down in the early hours of the morning, but it did not penetrate through the sleeping bag and I was still very warm. Another night witnessed -1.7° at Erldunda, I had no thermals just my normal pyjamas no socks and no inner fleece and I was very warm, did I mention comfortable. Perfect sleeping bag for car camping in the cold.
Thanks Snowys

- 2558

Will a large STS comfort plus insulated mat work with this sleeping bag?1 answer

Hi. I own a sea to summit comfort plus insulated large sleeping mat. Will I be able to fit it in the BT4's sleeping mat sleeve? Thanks!

- Bateman(5 months ago)

G'day Vishnu,

We've asked Sea to Summit about this one and they said that they've never heard of anyone having issues with getting their Large Comfort Plus Insulated Sleeping Mats to fit nicely in the Sea to Summit Basecamp Bt4 Long Sleeping Bag.

- Snowys(5 months ago)

Is this bag warmer and more long lasting than Roman -5 Palm Passport1 answer

Hi. I have a Roman Palm Passport and was happy with it until I washed it and now it is not warm enough for winter. Is this bag a warmer better quality bag than the roman and is the bulk worth it over just buying a new Roman - 5 palm passport bag? Down bags are not an option for me re ethics.

- Mayfield East(11 months ago)

G'day Jack,

The Sea to Summit Basecamp Bt4 Sleeping Bag is a much higher quality sleeping bag than the Roman Palm Passport, is rated to -8C and as long as you follow the care instructions included with the sleeping bag (Sea to Summit offer pretty comprehensive information), you should get many years of use out of the bag.

In regards to the bulk, that's probably only a question you can answer in terms of what you need it for and whether it is practical.

- Snowys(11 months ago)

What size sts compression dry sack and better than Roman Palm Passport1 answer

Hi I am interested in this sleeping bag. What size compression dry sack from Sea to Summit do you recommend?

- Mayfield East(11 months ago)

G'day Jack,

The Sea to Summit Basecamp Bt4 Sleeping Bag is a much higher quality bag than the Roman Palm Passport.

It also comes with its own compression sack and when compressed, has a volume of around 14.6 L.

- Snowys(11 months ago)

Suggested for late Spring Whistler, Canada?0 answers

Seeking a comparison between this bag and the Sea to Summit TkII Women's (please see my question posted against that product also). Which bag is suggested for late Spring in the Western Canadian mountains for a woman who feels the cold? Many thanks!

- Brisbane(1 year ago)

Can I remove the straps?1 answer

Will the pillow attachment and straps adjust enough to fit an Exped Downmat 9LW? Alternatively, can the straps be removed so they don't create lumps between the bag and the mat?

- Paynesville(1 year ago)

G'day Peter, 

I have just checked the display model that we have of the Basecamp BCII (we don't have the Bt4 on display, but it has same attachment system) and you can remove the straps and move them up and down the three mat loops positions on the bag. The straps are also very thin, so if you did leave them on, they wouldn't be much of a bother Peter. 

I have actually given this a go with the Downmat 9LW - and while it was a good 5-minute struggle, you can get it to fit onto the sleeping mat loops on the Basecamp bag. 

- Snowys(1 year ago)
Heads up! Our store in Brendale (QLD) doesn’t have footwear available for fittings. If you order online, your footwear will be sent from SA... quick-smart!
Heads up! Our store in Brendale (QLD) doesn’t have footwear available for fittings. If you order online, your footwear will be sent from SA... quick-smart!
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