The Mountain Hardwear Men's Micro Thermostatic Insulated Jacket is a great midlayer for alpine climbing because it packs away like a down jacket and stays warm when wet like a true synthetic. Thermal.Q Elite mimics down insulation's lofty warmth even though it's a protective synthetic, and it remains so compressible that you can stow it inside its pocket and clip it to your harness. Its lightweight insulation transcends alpine activities so you can take it backpacking, hiking, or climbing in the cold.