Sea to Summit Trek -1C Down Sleeping Bag

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Sea to Summit’s Trek -1C Down Bag provides versatile temperature control and comfort. It features 650+ fill duck down, a Free Flow zipper system for ventilation, and a generous semi-rectangular shape. The bag is not ultralight but offers a good balance of warmth, space, and adaptability.

Sea to Summit says: 

The Trek Down Sleeping Bag is the perfect option for vehicle-based travels and overnight camping. With 650+ FILL Power, this versatile and spacious bag uses an ergonomic design to offer additional warmth and comfort.

Our Verdict

Sea to Summit’s Trek -1C Down Bag delivers a sleep system with versatile temperature control and a spacious, comfortable fit. This semi-rectangular bag utilises water-resistant 650+ fill duck down to provide warmth rated to -2°C.

A key feature is Sea to Summit’s Free Flow zipper system, which has two sliders on the full-length and foot box zips and a half-length zip on the opposite side. So, it is a versatile bag with plenty of ventilation options if needed. The generous semi-rectangular shape offers roomy space.

Other features include a comfortable fitted hood, a draft collar that runs along both sides of the bag, vertical chest baffles, and a horizontal lower baffle that mitigates down shifting throughout the night. The 20D recycled polyester shell is light yet sturdy, and two length options provide a dialled fit.  

While not an ultralight minimalist bag, the Trek -1C hits an outstanding balance of warmth, roominess, and versatility.

– Reviewed by Ultralight Outdoor Gear

Features

• Duck Down with Ultra Dry Down treatment for improved water  resistance in damp conditions.
• Recycled polyester offers durability and comfort for lightweight  adventures in a range of climates and conditions.
• The Free Flow Zip System offers temperature regulation and  multiple sleeping bag configurations for added freedom in the outdoors.
• The Semi Rectangular Fit features a spacious design for added  comfort and room that is best suited to 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:1108g (excludes storage bags)
  
• Fill weight: 380g
  
• Fits up to: 6 ft / 185cm
• Internal Width Shoulder: 158cm
• Internal Width Waist: 149cm
• Internal Width Feet: 119cm
• Compressd Size: 13L

Long Specs

• Weight: 1200g (excludes storage bags)
  
• Fill weight: 437g
  
• Fits up to: 6 ft 6 in / 198 cm
• Internal Width Shoulder: 168cm
• Internal Width Waist: 159cm
• Internal Width Feet: 129cm
• Compressd Size: 13L

Fit

• Semi-rectangular fit: Spacious and generous, a roomy fit for car camping and the occasional overnighter.

Materials & Construction

• Insulation: 650+ FILL Power, RDS-certified, Duck Down with Ultra Dry Down treatment for improved water resistance in damp conditions
  
• Fabric: Recycled 20-Denier Polyester shell and lining.
• 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: Vertical chest baffles, horizontal baffles lower half and base, box wall baffle construction throughout.
• 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