THE JQRacing Differential Gasket Set includes 3pcs of the paper gaskets, enough for all three diffs. These gaskets are installed in between the ring, or spur gears, and the differential cups. They are the component that seals the differentials at the ring/spur gear. This package includes three differential gaskets.
In order for you to have a leak free diff, make sure that you dry both the surfaces before closing the diff. Be careful if you run another gasket, because changing the thickness of the gasket will change the internal mesh of the diff and could cause problems.