iMusi Fitness Tracker with Heart Rate Monitor Sleep Monitor Pedometer Wireless Bluetooth Smart Watches for Android and iOS Smartphones - Purple * Smart watch with Multi Function: Display date and time, heart rate monitor, tracking steps, record running and walking distance(km), calorie counter, sleep monitor. * Fitness Tracker Need App to Connect with Smartphone: Before use the pedometer. Please download app on your smartphone, and connect wristband watch with your smartphone by Bluetooth. * It is a Good Reminder for Your Phone Call and Message: Display incoming calling/message, viration reminding for Calls/SMS/WeChat/Facebook/Twitter/WhatsApp/Linkedin/Instagram/Messenger messages and clock alarm. Also enabled with camera remote capture,find phone and anti-lost alert functions. * Silicone Straps with button: Easy to get strap on, adjustable and comfortable to wear. Watch Strap Length: 270mm, Wrist circumference:14cm to 20cm.(5.5inches-7.8inches). * Compatible with IOS and Android Phones: Requires Android 4.4 or above, iOS 7.1 or above,Bluetooth 4.0 or above.Download APP by scanning the QR Code printed on the manual. You can download APP"Veryfit 2.0" from Play Store and Apple Store. Please note: this fitness tracker only support for android os and ios,can't support windows os phone.