Hot Chillys La Montana is aptly named: this men's heavyweight thermal is truly our king of the mountain for warmth. The fabric consists of brushed, micro-denier polyester fleece for lighter weight and greater strength and durability. But to ensure this men's thermal base layer top doesn't interfere with your active endeavors, we've placed stretch panels in key areas of this men's thermal zip-t layer for added maneuverability. All of this adds up to one layer that is meant to keep you warm and comfortable, no matter your environment or activity. Its unbeatable combination of practicality and comfort make it the perfect men's fleece for any adventure.