Which standard is used to communicate thread specifications based on metric measurements?

The ISO Metric Thread Standard is the correct choice for communicating thread specifications based on metric measurements. This standard is widely accepted internationally and provides a system for defining threads that includes parameters such as diameter, pitch, and profile. The ISO standard establishes clear guidelines that help ensure consistency and compatibility in threaded fasteners globally.

In contrast, the ANSI Standard is primarily focused on inch-based measurements and designations, making it less applicable for metric specifications. The SAE Standard also deals predominantly with inch-based systems and is used primarily in the United States for automotive and other engineering applications. The Metric Thread Designation, while it may sound relevant, does not refer to a formal standard but rather to the way metric threads can be identified. Therefore, it lacks the comprehensive structure found in the ISO Metric Thread Standard, which specifically addresses the nuances of metric thread specifications.