Merrell Men's Norsehund Beta Mid 6" Waterproof Suede TPU 1/2 shelled upper for protection and durability Bellows tongue keeps debris out 400g Merrell Opti-Warm lightweight, low-bulk, synthetic insulation keeps you warm in varying conditions 300g Merrell Conductor Fleece provides lightweight, versatile heat retention in varying conditions ColdSmart Thermal System regulates your temperature with airflow channels keeping your feet dry and warm