Smart band with heart rate monitoring and sleep tracking functions, and 5ATM water resistance. I have only used it in the sauna. It works without any problems. - Model Name: Smart Band 8 Active - Color: Black - Size: Fits wrist circumference: 155mm-219mm - Functions: Heart rate monitoring, sleep tracking, exercise recording - Water resistance: 5ATM - Battery capacity: 200mAh Thank you for looking.