USB data cable USB Micro-B to Micro-C, approx. 1m long. Used to connect the IC-705 to a smartphone with a USB Micro-C socket.
On the smartphone, you can then use, for example, the free Icom software RS-MS1A (Google Play Store) to control the radio, transfer data, update the relay lists etc.
If your smartphone uses a Micro-B socket, you need the OPC-2417 cable.