Victron VE.Direct Bluetooth Smart dongle:
The VE.Direct Bluetooth Smart dongle allows non-Bluetooth VE.Direct Victron products to be accessed via Bluetooth, for monitoring, changing settings, updating firmware and using the VictronConnect App. View information wirelessly such as battery status and solar panel power, plus other useful data.
The dongle is able to read data from any product that has a VE.Direct port and is especially useful for products that do not have built-in Bluetooth, such as the BMV 700 battery monitor, Phoenix Inverter VE.Direct or BlueSolar MPPT Solar Charge Controllers.
Manual here