The Mountain Equipment Women's Helium 3.8 Warm Zone self-inflating sleeping mat provides welcome comfort & insulation with a small packed size for year-round mountain use. The foam core has bilateral holes that help insulate you from the ground while ensuring your comfort & minimizing the mat’s packed size. The Warm Zone features a higher density foam in the torso area for better insulation & more comfort. A non-slip abrasion-resistant base prevents the mat from moving around as you sleep & a large push-in valve allows for rapid inflation & deflation.