Band Length: Both small and large sizes included in box.
Small: Fits wrist 5.1 - 7 inches in circumference
Large: Fits wrist 6.5 - 8.6 inches in circumference
Compatibility: This watches for men is compatible with a built-in Hi-Fi speaker and microphone, support most smartphones running iOS 9.0 and Android 4.4 or above.
OS Compatibility: This watches for men is compatible with a built-in Hi-Fi speaker and microphone, support most smartphones running iOS 9.0 and Android 4.4 or above.