When the mountains turn hostile and the stakes get high, the Patagonia R1 Thermal Jacket delivers the technical performance alpine climbers and mountaineers demand. This isn't just another fleece – it's a precision-engineered climbing jacket built for those coldest alpine objectives where every detail matters. The innovative dual-layer Technostretch construction combines a smooth, wind-shedding outer face with a moisture-wicking microgrid fleece backing, giving you the perfect balance of protection and breathability as you push through challenging mountain terrain. The ultra-stretchy recycled polyester fabric moves with you through every reach and stretch, while the slim fit design and strategically placed pockets won't interfere with your harness or pack. Whether you're tackling technical routes in variable conditions or need reliable insulation for cold weather mountaineering, this versatile mountain fleece adapts to your needs with a full-zip front for instant temperature control and low-profile cuffs that won't bunch up under gloves.