FB2-015 THERMOCOUPLE FITS DESA FB2-015

FB2-015B Thermocouple is the OEM replacement thermocouple for many of the heaters, fireplaces and gas log produced by DESA International and sold throughout the United States and Canada.

The outside copper coating of your new thermocouple will be flattened on purpose by the manufacture to stamp the parts number of the part and to prevent the thermocouple fixing nut from sliding down the copper wire.
This is “Not a Defect”