What is the symbol of the round black case with red edge, white background and red bar?

This kind of sign is related to safety or protection, and is usually called "safety belt" sign, also known as "safety triangle sign" or "safety warning sign".

This sign consists of a round red edge, a white background, a black pattern and a red bar, and its shape and color usually have specific meanings and instructions. White background represents safety, red borders and bars represent warnings, and black patterns represent specific safety functions or instructions.

This sign is often used in many fields, such as industry, construction, transportation, medical care and so on. For example, in the field of transportation, such signs may appear in car cabs, road intersections, railway tracks and other places to remind people to pay attention to safety, wear seat belts or take other safety measures.

In a word, this kind of circular red edge, white background, black pattern and red bar sign is usually considered as a safety warning sign, which is usually called "safety belt" or "safety triangle/warning sign". It is usually used to remind people to pay attention to safety and take necessary protective measures to ensure the safety of themselves and others.