World War II Navy Straight Key. It is identified as a "CMI-26003A", which translates as follows: 'C' for Contracted Out, 'MI' for Molded Insulator (the company that was contracted to make the key), '26' for Straight Telegraph Key, and '003A' for the model number and revision. Here is a website that shows you how to decode these keys: U. S. Navy Telegraph and Wireless Keys.