Plantronics M20/M50 Bluetooth Headset Date Code
The date code of your product designates its date of manufacture, and it can be used to establish your warranty period. The date code is generally listed with your product’s model and part number, although this is not always the case.
The chart below can assist with understanding the date code.
Example: If you see C1 on your product, the C is the month of March and the 1 is the year 2001.