av/drawable-anydpi-v21/ic_volume_down_black_24dp.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
        android:width="24dp"
        android:height="24dp"
        android:viewportWidth="24.0"
        android:viewportHeight="24.0">
    <path
        android:fillColor="#FF000000"
        android:pathData="M18.5,12c0,-1.77 -1.02,-3.29 -2.5,-4.03v8.05c1.48,-0.73 2.5,-2.25 2.5,-4.02zM5,9v6h4l5,5V4L9,9H5z"/>
</vector>