Color: Midnight w/ Large Black BandAccent your style while enhancing your fitness With our vvosmart 4 activity tracker. This slim, swim-friendly wearable comes loaded with fitness and wellness features to help you make the most of a healthier, more active lifestyle. A wrist-based pulse ox sensor lets you estimate Blood oxygen saturation while youre sleeping or you can Spot-check your oxygen levels anytime during the day. (This is not a medical device and is not intended for use in the diagnosis or monitoring of any medical condition) The device also monitors heart rate at the wrist and includes such helpful tools as all-day stress tracking, a relaxation breathing timer and Vo2 Max readings. Plus, body battery energy monitoring helps you know when youre primed to be active or when you may need to rest. Safe for the pool or shower, vvosmart 4 keeps you going strong with up to 7 days of battery life while Smart notifications with vibration alerts help you stay connected on the go (When connected to a compatible smartphone).