How to determine your correct SmartSleep device size?
Recommendations for choosing the right SmartSleep device size
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.