How to determine your correct SmartSleep device size?

DeepSleep Headband 1
Size M: Head circumference 51 – 60 cm (20.1” – 23.6”)
Size L: Head circumference 60 – 66 cm (23.6” – 26.0”)

DeepSleep Headband 2
Size M: Head circumference 51 – 58 cm (20.0” – 22.5”)
Size L: Head circumference 58 – 67 cm (22.5” – 26.4”)

Size medium will be the best size choice for approximately 70% of people.

If your head measurement falls at the end of the size and you usually wear a size L cap then please choose size L. 

Place a string or fabric tape measure around your head about 3-4 mm (1/8") above your ear, across the middle of your forehead, completely encircling your head. Hold the tape firmly, but not too tightly. If your head measurement falls at the end of size (for example, 60cm), choose the smaller size.