We have lots of customers who love using their Manta COOL Mask overnight. However, for most customers, we recommend using the masks below for overnight sleeping:Original Manta SLEEP MaskManta SLIM Mask Manta Sleep Mask SOUNDManta SILK MaskManta MAX MaskManta Sleep Mask PROThe eye cups we’re using in the above masks are made from polyurethane foam and are tapered on the sides to ensure your comfort regardless of what type of sleeper you are. The insides of the Manta COOL Mask are filled with beads which may be uncomfortable for some if used for long periods of time. Also, while the Manta COOL Mask can be used overnight, it was designed more for short usage (i.e. naps or when you need cold therapy for your headaches / puffy eyes). It only stays cool for the doctor-recommended duration of 10 minutes to protect the sensitive skin around your eye area from damage.