MIL-PRF-46846C (NOTICE 1), MILITARY SPECIFICATION: RUBBER, SYNTHETIC, HEAT-SHRINKABLE (25 OCT 2005) [SUPERSEDING MIL-R-46846B]., This specification covers the requirements for extruded tubing, molded parts, and extruded shapes that are flexible, electrical insulating and whose dimensions will reduce to a predetermined size upon the application of heat.