High temperature gasket material for use with a Retort Packing Gland. The gasket is used to seal the packing gland with wires installed to prevent steam/water from exiting the retort during testing. It comes in three options: A set of 4" Pre-Cut gaskets to fit a 1" Ecklund Packing Gland (#C24FL-GSK-4), a set of 5" Pre-Cut gaskets to fit a 2" Ecklund Packing Gland (#C24FL-GSK-5), or a 1 square foot piece of the gasket material (#GSK-MAT).