KODENSHI Fiber Gentle Warmth Technology: The KODENSHI Fiber eye mask utilizes your body's own natural heat to generate a comfortable, lasting warmth without the need for batteries or electricity. Near-Total Darkness for Quality Sleep: Designed with a superior 99.9% blackout rate to create the ideal sleeping environment, ensuring undisturbed, high-quality rest at home or while traveling. Full Coverage Comfort for Eyes & Ears: This generously sized design gently envelops both your eyes and ears, providing maximum light isolation and an embracing sense of security that leads to deeper relaxation. Breathable, All-Season Wear: The special fabric suppresses moisture to ensure comfortable, breathable wear, eliminating the clammy feeling often associated with heated masks. Stay cool in summer and cozy in winter. Durable & Effortless Care: Simply place in a laundry net and wash with your normal laundry; the KODENSHI technology remains effective after repeated washing. Compact design makes it easy to carry.