BTSShop Wireless USB Sync Dongle Replacement Bluetooth for Fitbit Flex/Force/One/Charge/Surge/Charger HR/Blaze/Alta Activity Trackers Syncs your fitbit activity tracker to your online account. Ideal for second laptop or computer. Compatible with Fitbit One, Flex, Force, Charge, Charge HR, Surge activity trackers. Newly upgrate to compatible with Fitbit Blaze and Fitbit Alta.( Note that only within 1 meter can the dongle better sync with your fitbit). Last please NOTE that this item does NOT fit for FITBIT ZIP model.Pay attention to this before purchasing.