This specification covers an irradiated, thermally-stabilized, flame-resistant, modified silicone rubber in the form of heat shrinkable tubing. Primarily for use as a flexible, electrical insulation tubing whose diameter can be reduced to a predetermined size by heating to 175 degrees C (347 degrees F) or higher. This tubing is stable under the following conditions: -70 to +180 degrees C (-94 to +356 degrees F) Continuous; -70 to +300 degrees C (-94 to +572 degrees F) 4 hours.