Pyrolytic Graphite is a unique form of graphite manufactured by decomposition of a hydrocarbon gas at very high temperature in a vacuum furnace. The result is an ultra-pure product which is near theoretical density and extremely anisotropic. The material is deposited as graphene and grown onto a substrate giving it a layered composition with anisotropic properties. This means it has different properties across different planes. In the C plane (across its layers) it has low thermal conductivity, acting as an insulator. In the A-B plane (with the layers) it has very high thermal conductivity, acting as a superb conductor. Our pyrolytic graphite discs and plates are available in three different materials: Substrate Nucleated (PG-SN), Continuously Nucleated (PG-CN), and High Conductivity Substrate Nucleated (PG-HT). Continuously Nucleated (PG-CN) material has physical properties 15-20% higher than that of Substrate Nucleated.