Idea of Letterbox Icon
A mailbox with a horizontal slit on the door and a handle on one of the sides. The handle is raised high. The front profile of the box is rectangular down below and rounded up top, like a house door. From the side, it has a rectangular profile. The entire box is on top of a slim post.
This is a Letterbox icon. It is available in PNG and vector. Downloading is free for PNGs up to 100x100px.