The Hot Chillys Kids' La Montaña Bottoms might be very light and soft, but they are a powerhouse of warmth! Micro-denier polyester yarns are used to make it super warm without being thick and bulky. These heavyweight base layer bottoms are brushed with an anti-pill finish on the face to keep them looking nice, and Moisture Transfer Fibers to make sure the fabric stays dry. The Hot Chillys Kids' La Montaña Bottoms are sure to keep the kiddos warm, dry and super comfy so everyone can have fun!