Your Personal Wind-Down Ritual Make time to slow down with the MongDa V3 Smart Sleep Mask. Combining immersive relaxation sounds, gentle warmth, cooling comfort, and full light blocking, MongDa V3 is designed to make your personal downtime feel more comfortable and enjoyable. From your nightly wind-down at home to quiet moments on the go, its thoughtfully designed features create a more relaxing environment wherever you are. Less light. More comfort. Your time to unwind.