- Size: One size • High-quality polyester cotton thermal socks, soft. • Magnetic interior design, flip when using. • Self-heating tourmaline bottom to keep warm. • One size fits most men and women. • Suitable for outdoor activities: climbing, skiing, fishing, jogging, hunting, cycling, hiking. • Quickly keep warm by rubbing them with your feet. • Relieve fatigue and promote blood circulation. • Material: Tourmaline, Polyester Cotton. • Color: Black. • Includes 2 pairs of self-heating socks.