REX Graphite Rings are maufatcured normally in a range of densities from 12 g/cc to 1.8 g/cc with carbon content ranging from 99% to 99.85% Corrosion and Oxidaton resistant grades and PTFE impregnated grades also supplied, Flexible and highly impermeable to gases and liquids. Metal tipped graphite molded rings to cusomer drawings are available for high pressure/anti extrusion applications. These rings have high thermal conductivity and don't contain any Adhesive or Binders and have self lubricating properties and is therefore virtually maintenance free.