The image is of a mailbox with the door opened. The flag is up on the right side of the box. Part of an envelop is showing inside the box. The back of the envelop is showing the seam where the envelop was sealed.
This Postal 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 5,700 icons, all in the same style and quality.