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Seamless Alpine Burrow Bag Thermal Sheet

Style #1121440

  • 50℉

Price: $129.00

Member Points: 645    ?

Delivering versatile use as a sleeping bag liner and on its own as a lightweight sleeping bag, its seamless design maximizes heat retention by allowing the insulation to loft fully, while the airtight outer surface efficiently holds your warmth. The inside features the Spiral Stretch System that orientates the fabric and stitches diagonally to promote a horizontal stretch which gently cocoons your body without feeling restrictive.


GM (Gunmetal)


Updated 05/19/24 07:10 (EST)

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Actual color may vary.


  • Spiral Stretch System (inside)
  • Anti-snagging slider cover
  • Tapered Spiral Stuff Sack included (US patent No. 8,801,286)
  • Use the stuff sack as a pillow by filling it with clothing and attaching it to the bag's loop


Weight1 lb 3.1 oz (542 g)
InsulationEXCELOFT (100% polyester)
Material30-denier Super Multi (multi-filament) polyester taffeta (water repellent finish)
Compressed sizeØ4.7 x 9.4 in (Ø12 × 24 cm), 2.4 L
Country of originVIETNAM
OtherTargeted thermal guideline: 54°F / 12°C (comfort), 48°F / 9°C (lower limit)
Adds around 9°F / 5°C of warmth to the temperature when used as a sleeping bag liner
Max User Height: 6 ft / 183 cm
Zipper Length: 39.4 in / 100 cm

<Montbell sleeping bags stretch>
Shoulder girth when relaxed: 55 in / 141 cm
Shoulder girth when stretched: 63 in / 161 cm
Knee girth when relaxed: 45 in / 113 cm
Knee girth when stretch: 51 in / 129 cm

Excelent Stretch to Provide Better Sleep (Burrow Bag)

The Spiral Stretch System (US.Patent No.7,900,301) is what made Montbell sleeping bags famous. The ability of the bag to move with you during the night has provided comfort for many. Our sleeping bags featuring seamless construction are no different. Although the exterior of the bag is a solid piece of fabric, the interior of the bag features a combination of the fabric's mechanical stretch and elastic stitching. The result, the sleeping bag hugs and moves with you as you sleep, but doesn't feel restrictive. This also means that as you move, gaps between you and the sleeping bag are less likely to form and maintains even coverage of the sleeping bag, maintaining your warmth.


Tapered Spiral Stuff Sack

Utilizes the same bias cut fabric used for our Spiral Stretch System. Because the fabric stretches, it's possible to alter the shape of the sleeping bag to some degree so it fits in the available space of your backpack. The opening to the stuff sack is wider to enable easier stuffing.

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