Insulating layer

Purpose

Hold body heat during breaks, waits, and the cold that follows sweat.

Used in kits

• Alaskan Float Trip Fishing Kit

  Fishing

• Ice Fishing Day Kit

  Fishing

• Kayak Day Trip Safety Kit

  Boating & Paddling

• Ultralight Overnight Backpacking Kit

  Hiking & Backpacking

• Search and Rescue Field Team Kit

  Professional & Field Ops

• Portable Astrophotography Kit

  Hobby & Making

• Drone Field Operations Kit

  Hobby & Making

Alternatives

• Fleece— Warm when damp and cheap; bulkier than a puffy.
• Down puffy— Warmest per ounce; useless once soaked.

Maintenance notes

• Store uncompressed so loft recovers.

Buying considerations

• Synthetic fill keeps working when wet — the safer choice for boats and cold rain.
• A layer you’ll actually carry beats a warmer one you leave behind.