When your pre-dawn alpine start has you layering up before the sun hits, the Black Diamond First Light 1.0 Stretch Vest delivers the perfect balance of warmth and breathability for high-output winter adventures. Built with migration-resistant PrimaLoft Gold Active insulation and a merino wool backing, this versatile midlayer moves seamlessly from frigid skin track ascents to sweaty ice climbing pitches without overheating or leaving you chilled. The lightweight 20d stretch nylon ripstop shell shrugs off weather while flexing with every dynamic movement, whether you're powering through a cold morning run or navigating technical terrain by headlamp. When the day warms up or you're generating serious heat, it packs neatly into its own chest pocket, making it an essential piece for any serious mountaineer's kit who demands reliable performance across changing conditions.