The Helly Hansen LIFALOFT Insulator Jacket runs on lightweight, highly compressible LIFALOFT insulation built to work alone on a cool day or packed into a bag as a layer for a colder one. A PFC-free DWR treatment and windproof construction keep it relevant past just calm, dry weather, so it earns a spot in a pack even when the forecast isn't certain. It compresses down small enough to disappear until the temperature actually drops. What Our Gearhead(R) Experts Are Saying:"I packed this down to almost nothing on a trip and wore it solo on a mild afternoon, then zipped it under a shell once the temperature dropped that night. That kind of range is what makes it worth the space in a pack."