Equipped with Bluetooth button. Elastic cotton sock with DUAL POWER heating system allows you to use socks with different types of power supply: Possibility of adjusting the button and viewing the battery life on the button or via app directly on the smartphone. Colors: Black. Comfort: Electrically heated. Functionality: Battery life indicator. Style: Touring Adventure, Casual. Suitable for: Men, Universal, Women. Climate type: All types of climate. EC type-approval. Size S (37-40), M (41-44), L (45-48).