Summary

This is the 3" PZM arm described in the Build a PZM Microphone UPDATED! Instructable by Jules Ryckebusch: https://www.instructables.com/Build-a-PZM-or-Pressure-Zone-Microphone/

For more information, please see his Instructable. It has all the details for building a pressure zone microphone using these parts and the other parts listed in his article.