Made of felt, simple, lightweight, and perfectly insulating the foot from the cold. Provides the right temperature for the feet, and by lining the bottom of the shoes, it prevents the formation of blisters and the destruction of the lining. The softness of the felt also improves comfort when wearing footwear. Recommended for autumn and winter shoes, work shoes, and home slippers. Should be replaced regularly. When choosing a size, please refer to the size chart.