Halogen-Free Liquid Tight Cordgrips Heyco Halogen-Free Liquid Tight Cordgrips are molded from nylon 6/6 which will not burn or produce toxic fumes in the event of a fire. The IP68 rated series is approved for NEMA 6 and 6P applications and resists salt water, weak acids, gasoline, alcohol, oil, grease, and common solvents. The Halogen-Free Liquid Tight Cordgrips from Heyco have a sealing nut assembly with a ratchet design which provides protection against vibration and ensures a firm grip on the cable.