A mechanical seal primarily consists of two flat surfaces that are pressed together to contain the fluid within a pump or other equipment. When considering the 40mm mechanical seal, it's important to understand its components, which typically include a stationary ring, a rotating ring, spring mechanisms, and gaskets or o-rings. The stationary ring is mounted to the pump housing, while the rotating ring is attached to the shaft. When the pump operates, these rings slide against one another under a thin film of the fluid, effectively sealing the chamber and preventing leaks.