This Skrzynka pocztowa zamknięta - flaga w górę 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 4,300 icons, all in the same style and quality.
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.