A climb that starts cool heats up within minutes, and the Mons Royale Bella Merino Long-Sleeve Hooded Top handles that swing as a lightweight merino base layer top whose half-zip hood adjusts coverage as conditions change. The Merino Air-Con fabric blends merino wool with nylon and elastane for stretch, and raglan sleeves and a contoured side body let the slim fit move with the body. What Our Gearhead(R) Experts Are Saying:"On long climbs, the merino mesh back vented the heat that built across my back, and the top stayed dry as the effort picked up. The underarm mesh gusset added airflow right where the sweat started."