The Men's Patagonia Nano-Air Ultralight Full-Zip Hoody is a lightweight insulation piece for climbing. The changing temperatures of the mountains mean you're going to need to layer up, and this piece fits the bill as a mid or outer layer. The 100% recycled polyester ripstop shell and lining features mechanical stretch for movement, abrasion-resistance, and a durable water repellent finish for moisture-resistance. The 20g FullRange insulation is light and stretchy to warm you up, while still allowing breathability.