The Mechanical Seal has two flat seal faces at right angles to the axis of the rotating shaft, preventing shaft wear. One is the seal face of the rotating seal ring and the other is the seal face of the stationary seal ring (stationary, seat or floating seat). One seal face (rotating seal ring) is allowed axial motion to permit the seal faces to remain in contact with each other despite endplay of the shaft, wear or runout of the seal faces. The seal ring is flexibly mounted on the shaft and rotates against the stationary seal ring. The seal ring has a resilient packing, called shaft packing (O-ring or V-ring assembly) that allows the seal ring to slide back and forth along the shaft and at the same time prevent leakage between it and the shaft or sleeve as a secondary seal. The stationary seat is backed against the gaskets (mostly O-rings) to prevent leakage around its back.