Big Agnes Bolten SL 20 Degree Sleeping Bag – Stretchy & PrimaLoft

Big Agnes Bolten SL 20 Degree Sleeping Bag is very light, constructed with stretchy fabric and filled with PrimaLoft insulation, suitable for wet conditions for hikers and backpackers.

Key features

What type of the bag is this & what is in the name

As you realize from the pictures, this is a mummy-style bag with an offset quilted construction. It looks as narrow as you might expect from such a design, but here you have something extra. On both sides you have wide sections that run all the way along the bag and those are built from a very stretchy fabric.

The letters SL should imply ‘superlight’. This is indeed so for a bag with synthetic insulation, you will see how it compares with some of its competitors, there is a comparison table below.

Who is it for

Size: They build this Bolten SL 20 bag in two sizes, regular (R) and long (L). So this determines the corresponding users, you can choose your size to avoid unnecessary weight. The two sizes fit people up to 6 feet (183 cm) and up to 6 feet 6 inches (198 cm), respectively.

Seasons: In view of its 20 F (-7 C) temperature rating, this is a true 3-season sleeping bag even if you add a few degrees for comfort.

Weight: In spite of the letters SL in the name, this is not a superlight backpacking bag. There are lighter options on the market. But here you have the top-notch synthetic insulation which is supposed to perform better than down in wet conditions. So carrying a few grams more may be worth the effort.

Packed size: This bag is highly compressible. However, it does not come with a compressible sack. So to compress its R version to 8 x 6 inches (20 x 15 cm) as mentioned around on the Internet, you would have to order a separate sack. With the sack included in the package, the packed size is far less impressive 17.5 x 8 inches (45 x 20 cm).

So all in all, this is a bag for backpackers and hikers, and if good for them this also implies that it is suitable for practically any outdoor activity. But for ordinary camping, I guess you would rather use something much wider.

Materials & construction

The insulation

Here you have the best what synthetic insulation can offer. This is a combination of PrimaLoft Silver & PrimaLoft Gold Active insulation. The latter is used in the stretch side panels.

The fabric

You have a nylon ripstop shell with a water repellent finish and the mentioned side panels are a polyester Spandex stretch. The lining is a polyester taffeta. With those stretch panels you are less constricted and you can bend your knees at least up to a point.

Other features

• Low profile cord lock to cinch the hood with one hand.
• Anti-snag draft tube is there to prevent heat loss.
• Zipper garage on the top.
• Interior fabric loops for a bag liner.
• Exterior loops for drying or storage.
• Mesh storage sack & nylon stuff sack are included.
• YKK #5 zipper.

Please see a bit more in this short video by the brand:

Specifications

• Type: mummy bag.
• Sizes: R & L.
• Weight:
  – R: 2 lb 11 oz (1.22 kg).
  – Long: 3 lb 1 oz (1.34 kg).
• Fill: PrimaLoft Silver & PrimaLoft Gold Active stretch insulation.
• Fill weight:
  – R: 32 oz (909 g).
  – L:  36 oz (1009 g).
• Fit:
  – R: up to 6′ (183 cm).
  – L: up to 6′ 6″ (198 cm).
• Girth shoulders/hips/knees:
  – R: 56/54/36 in (142/137/91 cm).
  – L: 60/58/40 in (152/147/102 cm).
• Stuff bag size: 17.5 x 8 in (45 x 20 cm).

Big Agnes Bolten SL 20 Bag vs Competitors

I have decided to show this Bolten SL 20 side by side with one synthetic fill bag and one down fill bag, so you can get some idea about the weight and the packed size. The Kelty’s bag is with the same temperature rating and also synthetic, and as you see it is considerably heavier. Its stuff sack is compressive and its packed size is better. Note this is a very affordable bag and with some really great features.

The Nemo’s bag is with a better temperature rating yet it is still lighter. This is because of its 650-fill Nikwax Hydrophobic down. It comes with a compressive stuff sack so the packed size is better. The price is almost the same. Please follow the links for updates.

Final thoughts, rating, pros & cons

Please see how I rate it, the same criteria are used for all the bags here in the site:

Big Agnes Bolten SL 20 Degree Sleeping Bag

8.6

Weight

8.2/10

Packed size

8.4/10

Temperature rating

9.0/10

Comfort & features

8.9/10

Pros

• Top-quality fill.
• Top quality zippers.
• Stretch fabric.
• Very light.
• Interesting and unique design.

Cons

• Expensive.
• No compressible stuff sack.

If you need more options to consider, please visit my page with sleeping bags. Check also my list with best 3-season sleeping bags, you will find a variety of designs. Check for example their Big Agnes Mystic UL 15 bag which is with a top quality down fill and lighter. If you need something ultralight and ultra-packable see this Therm-a-Rest Hyperion 20 Degree Sleeping Bag.

Note that this is not a sponsored post and I am not paid by the brand. Please use the comment box below in the case of questions or comments.