Built with an advanced sensor, the LetsFit IW1 smart watch can help you understand how well your body is absorbing oxygen (SpO2) when you sleep or even during the day. You may want to measure your SpO2 when you are climbing mountains or staying in an oxygen-poor environment. People with chronic health conditions including asthma, heart disease, and chronic obstructive pulmonary disease may also need to monitor their blood oxygen levels, especially during the night. This smart watch also measures your heartrate and steps. It’s splash-resistant. The wireless earbuds have a Talking/Playing Time of 4-5 hours per charge (Up to 30 hours with charging case).