Not sure this is from the Autolite web site.
Autolite Professional Series Wire Sets are designed to meet or exceed OES design requirements. The high-tech nylon reinforcement in the wire provides increased terminal retention and improved jacket adhesion. The tougher silicone jacket is less likely to tear away from the insulation.
Product Features:
Designed to meet or exceed OES design requirements
High-temperature, moisture proof, silicone boots
Increased terminal retention and strength properties
Features necessary accessories, silicone content and boot designs