Sea to Summit

Spark 15

Name: Spark 15
Brand: Sea to Summit

EU unverified

1lb 9.7oz for 29°F comfort: 850-fill down in vertical box baffles, 360° collar and full draft tubes. Independent testers flag the 10D shell as the tradeoff for that weight.

$549 typical

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EDITION 01RESEARCHED 2026-08-143 SOURCESREFRESH DUE 2027-02

SUBSTANCE SCORES

substance8.4/ 10

design7.5/ 10

value8.1/ 10

WHY THE PRICE IS JUSTIFIED

This is expensive but not status-priced: the weight, 850-FP down, vertical box baffles, full draft tube and 360° collar are independently observed performance hardware. It is the only premium-priced selection.

MATERIALS

Insulation850-FP RDS goose down

High-loft down delivers excellent warmth per gram.

BafflesVertical box-baffle construction

Limits down migration and avoids stitch-through cold lines.

Shell and liner10D fabric

Very low weight and soft hand, at a durability cost.

CRITERIA

9/10

Thermal Truth

Independent testing reports 29°F comfort and warmth on 20–25°F nights.

10/10

Insulation Efficiency

850-FP down in vertical box baffles.

9/10

Fit And Drafts

Wider mummy fit, 360° collar and substantial draft tubes.

7/10

Moisture Resilience

Down remains moisture-sensitive; use a dry bag.

10/10

Weight And Packability

1 lb 9.7 oz unisex weight in independent test.

7/10

Construction Durability

Reviewer flags thin material and shorter expected life.

7/10

Usability And Repair

Simple controls; zipper can snag and no stash pocket.

IDEAL FOR

·long-distance backpacking
·side or stomach sleepers who still count grams
·dry-climate alpine three-season trips

NOT FOR

·abrasive campsites or dog-heavy use
·users who need broad ventilation range
·buyers seeking budget value

DESIGN & ERGONOMICS

A little wider through shoulder and hip than rival ultralight mummies, with a large hood, full draft tube and 360° collar. The main UX flaw is a snag-prone zipper and no stash pocket.

LONGEVITY

Treat the 10D fabric as performance equipment: protect from abrasive ground, store loose and carry patch tape. Independent testing specifically cautions that its thin fabric is less durable.