In my Bluetooth settings, I can see two ZeBracelet: ZeBracelet2 and ZeBracelet2 BLE, Is it normal?

Yes, actually ZeBracelet2 is equippped with two Bluetooth chipsets: 2.1 and 4.0

- ZeBracelet2 corresponds to Bluetooth 2.1 channel

- ZeBracelet2 BLE correpsonds to Bluetooth Low Energy 4.0 channel