This Mute icon is made in Material Design style developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 5,300 icons, all in the same style and quality.
It is a classic mute icon. There is a basic speaker with the letter "x", or what could be a cross icon to the right of it. You can clearly see the back and front of the speaker. You would not think sound is coming out of this speaker.