What is a reciprocal heading on an underwater compass?

A reciprocal heading on an underwater compass refers to the direction that is exactly opposite to a given heading. For example, if you are heading at 90 degrees (east), the reciprocal would be 270 degrees (west). This concept is essential for divers to understand their exit route or return path, ensuring they can navigate back to their starting point effectively. It helps in maintaining orientation and preventing disorientation underwater.