* Coatings for Twist-Off style bolt assemblies shall be agreed upon between the producer, supplier and user, and are not permitted except when applied under the direction of the manufacturer. The coefficient of friction classification code does not apply to Twist-Off style bolt assemblies.
** Specification F3393 is a consolidation and replacement of three ASTM standards which included qualified coatings F1136/F1136M Bolt & Washer Grade 3, Nut Grade 5, F2833 Grade 1, and F3019/F3019M Grade 4.