Selfie sticks for an underwater camera are connected via Bluetooth. In order to also take photos with the selfie stick, the camera must therefore have a Bluetooth function. To connect a selfie stick to a smartphone, you can either use a Bluetooth function or the AUX connection.
The selfie stick extends your arm and allows you to take better pictures of yourself. However, many selfie sticks for underwater cameras are only suitable for recording videos, as they cannot be connected directly to the camera's shutter release. In order to be able to use the full photo recording function, the underwater camera must therefore be equipped with a Bluetooth function.
The connection with the smartphone, however, is somewhat easier. Some selfie sticks can be connected directly to the smartphone via an Aux connection.