Ascent -1C Down Sleeping Bag

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The Sea to Summit Ascent is a lightweight sleeping bag ideal for three seasons. Its 750+ fill power of responsibly sourced duck down provides warmth and is treated to maintain performance in damp conditions.

Sea to Summit says: 

The Ascent Sleeping Bag is the most versatile in our sleep range and is suited to a multitude of climates, conditions, and adventures. From long distance hiking to weekend getaways, the ultra lightweight 750+ FILL Power offers added warmth in cooler climates while the Free Flow Zip System allows for added air flow and ventilation in warmer climates. Putting comfort and adaptability at the forefront, the Ascent Sleeping Bag is a premium option for versatile adventures.

Our Verdict

The Sea to Summit Ascent is a versatile and lightweight down sleeping bag ideal for cooler, 3-season overnight conditions. With an EN comfort rating of -1°C (30°F), it provides just the right amount of warmth for nights hovering around freezing.

Premium 750+ fill power responsibly sourced duck down gives the Ascent an impressive warmth-to-weight ratio. The down insulation is treated to maintain performance if the bag gets damp from condensation or light precipitation.

The Ascent’s free-flow zipper system regulates ventilation and makes it adaptable. On warmer nights, you can open the entire side zipper or cinch it down to take advantage of the full mummy shape when temperatures drop below freezing.

Other key features include a spacious, relaxed mummy fit, adjustable drawcord hood, waterproof, breathable shell over the hood/foot box, and draft tubes to prevent heat loss.

At just 777g for the regular size, the Ascent packs down remarkably small yet still hits its -1°C rating when fully cinched – making it ideal for ounce-counting backpackers. Just bring extra insulation if you anticipate nighttime lows much below freezing.

– Reviewed by Ultralight Outdoor Gear

Features

• Duck Down with Ultra Dry Down treatment for improved water  resistance in damp conditions.
• The Free Flow Zip System offers temperature regulation and multiple sleeping bag configurations for added freedom in the outdoors
• With a spacious design, adjustment cord and room to fit a regular Sea to Summit pillow, the Technical Regular Hood offers comfort and flexibility for car camping and shorter adventures.

Specifications

Temperature Rating

• EN13537:2012 Comfort: 3°C | 37°F
• EN13537:2012 Comfort Limit: -2°C | 28°F

Regular Specs

• Weight: 777g (excludes storage bags)
  
• Fill weight: 300g
  
• Fits up to: 6 ft / 185cm
• Internal Width Shoulder: 158cm
• Internal Width Waist: 146cm
• Internal Width Feet: 119cm
• Compressd Size: 8L

Long Specs

• Weight: 864g (excludes storage bags)
  
• Fill weight: 343g
  
• Fits up to: 6 ft 6 in / 198 cm
• Internal Width Shoulder: 168cm
• Internal Width Waist: 156cm
• Internal Width Feet: 129cm
• Compressd Size: 8L

Fit

• Relaxed Mummy Fit: A more relaxed yet tapered mummy fit with high thermal performance.

Materials & Construction

• Insulation: 750+ FILL Power, RDS- certified, Duck Down with Ultra Dry Down treatment for improved water resistance in damp conditions.
• Fabric: Recycled 20-Denier Nylon shell and lining. 10-Denier Nylon waterproof-breathable hood and footbox.
• Zipper: Free Flow Zip System: Primary zip – full length #5 with zip-plow and two sliders.
  Secondary zip – 1/2 length #5 with zip-plow and two sliders.
  Footbox zip – #5 with two sliders.
• Baffle Construction: Vertical chest baffles, horizontal baffles lower half and base, box wall baffle construction throughout.
• Collar: Fitted front draft collar: scalloped over the neck and oversized at the shoulders.
• Hood: Generous fitted hood with two soft touch adjustments. Fits a Sea to Summit regular pillow.
• Draft Tube: Single, synthetic-filled, draft  tube along the top of all zippers.
• Intergration: Pairs with Women’s Sea to Summit bags, and STS quilts.

Help & advice:

• The Ultimate Guide to Lightweight Sleeping Bags
• Time-Saver Guide to Choosing a Sleeping Bag
• Sea to Summit Sleeping Bag & Quilt Guide
• About Sea to Summit
• The EN13537 Standard
• All About Down