Check the listing for details. Wellue SleepU Oximeter Continuous Tracking Heart Rate Blood Oxygen Saturation. Condition: Seller refurbished. Listed at 179.99 USD. Specification： WEIGHT：1.09 oz / 31gDEVICE DIMENSIONS：1.6'' x 0.9'' x 0.5'' RING PERIMETER：2.0'' - 3.0'' / 50-76mmWIRELESS：Bluetooth 4.0 BLE BATTERY LIFE：Rechargeable lithium-polymer, 3.7 Vdc, 16 hours for typical useDEGREE OF DUST &WATER RESISTANCE：IP24 RECORDED PARAMETERS：Oxygen levels, pulse rate, motion COMPATIBLE COMPUTER SYSTEM：Windows 7/8/10；macOS 10.15.3 or aboveWORKS WITH：iOS 9.0 or above, iPhone 4s/iPad 3 or above; Android 5.0 or above, with Bluetooth 4.0 BLEOXYGEN LEVEL RANGE：70%-99%PULSE RATE RANGE：30 to 250 bpmMEASURE INTERVAL：1S DISPLAY INTERVAL IN APP：4S BUILT-IN MEMORY：4 sessions, up to 10 hours for each session Note: It's not a medical device. This device is for Sports and Aviation use only and not intended for medical use. 1X SleepU smart wrist oxygen monitor 1X USB cable (Micro) 1X User guide Detail： 【1】Designed for oximetry monitoring：Continuously track your oxygen level, pulse rate and body movement all-day, collecting data every 4 seconds. Accurate and reliable.【2】Smart Reminder: Support you to adjust the threshold and vibration intensity on the mobile phone Vihealth APP. If your oxygen reading exceeds the set threshold, SleepU vibrates intelligently to remind you.【3】Powerful APP&PC reports: Transfer data to smart phone APP and PC software for more detailed information.It supports manage, review, analyze historical data and sharing JPG or CSV reports with others.【4】Free your fingers: The patented comfortable soft silicon RING sensor is light and convenient, and will not easily slip off your fingers during sleep. The probe can be replaced.【5】Built-in memory: SleepU can store 4 groups of data, each group can up to 10 hours. The data is automatically synchronized to the APP via Bluetooth, and the APP can store unlimited groups of data.【6】Rechargeable, long battery life. It can be used for 16 hours after fully charged.【7】Easy to use. The device runs automatically when you wear it.