Save files to SD Card

Unity Engine
1

Hello,

string fullPath = Application.persistentDataPath + "/video.mp4";
        File.WriteAllBytes(fullPath, www.bytes);

I have the above script that save a video file into the projects persistentDataPath. But this app is going is going o be exported on android and I would like that video to being saved on the SD card on a folder called videos.

How exacly can i do that by changing the fullPath string.

2