This "Like a Kotatsu" series, using patented technology to warm you from the feet up, is designed for sleeping. Addressing the concerns of cold feet preventing sleep and the anxiety of needing to sleep, it offers three sleep-inducing features to provide warmth like a kotatsu, warming your feet to the tips of your toes. 【For Cold Prevention During Sleep】It thoroughly covers the soles of your feet, where blood vessels are concentrated, warming them to the tips of your toes. The open-toe design allows for comfortable use during sleep without causing your feet to get stuffy.