Mountain Equipment Sigma Women's Jacket

For over 15 years, the Sigma Jacket has set the standard for down insulation in alpinism. Lightweight, packable, and highly water-resistant, it’s a top choice for serious mountaineering, offering warmth and protection without unnecessary weight or bulk on multi-day expeditions or technical alpine climbs.

The jacket features 800-fill power goose down, distributed strategically and held by stitched-through baffles to prevent cold spots, especially in areas like the shoulders, chest, and hood. The down is DOWN CODEX approved, and sourced through a transparent and audited supply chain.

The Drilite Loft outer fabric is lightweight, highly water-resistant, and windproof, allowing the down to fully loft while protecting against snow, ice, and wind. Seam-free shoulder panels and an extended inner hem and hood lining add extra protection against moisture.

The Active Alpine Fit is tailored for alpinists, reducing excess bulk while maintaining full freedom of movement, whether climbing, packing, or handling ropes.

The insulated hood, with Firestorm construction, combines a baffle design with an outer layer to protect against harsh conditions. Pleated baffles reduce bulk but maintain warmth, while a halo baffle shields the face from cold winds.

Inside, two large drop pockets provide easy access to gloves, hats, or other essentials during alpine pursuits.

Features

• DRILITE® Loft outer fabric is windproof, breathable, and water-resistant, keeping you protected and comfortable.
• European Goose Down insulation provides an excellent warmth-to-weight ratio and is highly compressible, and durable.
• Stitched-through baffles, some with pleats, improve loft and boost thermal efficiency.
• The Mountain HC Insulated Hood is fully adjustable with rear and front adjusters and fits over a climbing helmet.
• Hybrid Hood Construction offers a protective shell that enhances insulation efficiency.
• Two large hand pockets are easy to access with a pack or harness and can fit gloves.
• Two inner stretch mesh pockets for storing gloves or accessories.
• Packs into a small included stuff sack for easy storage.
• Built for long-lasting durability.
• Designed in the UK and manufactured in a Fair Wear Foundation-audited factory in China.

Specifications

CONSTRUCTION

• FIRESTORM hybrid Construction (Hood Only)
  
• Stitched-through baffles with pleated finish
  
• 9.5cm baffle height
  
• Bound Seams

POCKETS

• Hand Pockets - DRILITE® Loft anti-snag draft backer
  
• Inner Pockets - Stretch Mesh

HOOD

• Mountain HC Insulated Hood
  
• HALO baffle
  
• Internal hood cord routing
  
• Internal Duraflex® cord locks
  
• Rear tab volume adjuster
  
• DRILITE® Loft anti-wick lining

CUFFS & SLEEVES

• Pre-shaped sleeves
  
• Elasticated cuff with Velcro® fastener

HEM

• Adjustable – drawcord pullers (2)
  
• Dual-tether hem drawcords wont snag
  
• Drop Rear Hem
  
• DRILITE® Loft anti-wick lining

ZIPS

• Centre Front: YKK® #5 VISLON® zipper with 2-way non-locking slider
  
• Pockets: YKK® #3 VISLON® zipper with non-locking slider

PERFORMANCE

• Hydrostatic Head: 900mm (ISO 811)
  
• Breathability: MVTR: 7000g m2 24h-1
  

Video

Technology

	Down Cycle The recycled down Mountain Equipment use comes entirely from post-consumer goods - unwanted clothing and bedding collected by waste recycling companies.
	Drilite Loft Drilite® Loft is Mountain Equipment's exclusive range of highly water-repellent fabrics used in their insulated clothing and equipment. The original Drilite® Loft introduced almost 30 years ago, was years ahead of its time: a highly breathable, lightweight, and very water-repellent fabric. Those three hallmarks continue with their modern Drilite® Loft fabrics.
	Fair Wear As a member of Fair Wear, Mountain Equipment is committed to implementing the highest standards of working conditions.
	Down 700 Down is the finest insulator. Its warmth-to-weight ratio, compressibility, long lifespan, and softness are yet to be matched by manmade insulations. For all but the most serious expeditions, Duck Down is a great choice for both insulated clothing and equipment.