Bradychan Wireless Bluetooth Compatible with Fitbit Alta/Blaze/Flex/One/Force/Charge/Charge HR/Surge Wireless Activity Wristband Tracker USB Sync Dongle Note: The best syncing distance between the fitbit tracker and dongle is within 1m . Compatible with Fitbit Alta/Blaze/Flex/Force/One/Charge/Surge/Charge HR Activiity Trackers Plug into USB port. The bluetooth USB sync dongle is compatible with Fitbit Alta/Blaze/Flex/Force/One/Charge/Surge/Charge HR Activity Trackers. Note:the devices are not supported on OS X 10.5 and Windows XP. Download the Fitbit app for iOS, Android, or Windows Phone to set up.Any other problem please check the url link:https://www.fitbit.com/cn/start?platform=winxp