This is a mini-female connector that is designed to be mounted into a panel.  Also referred to as a bulk-head connector.

The durable plastic housing is made from black nylon and is stable up to 356ºF or 180ºC Celsius.

The connector is made from the compensating metals:  Iron and Constantan (same as the thermocouple material) and will not interfere with the signal. Be sure to hook up this connector to the measurement device using thermocouple extension wire, not copper wire. 

• J-type female panel mount thermocouple jack or socket
• Fits miniature flat J-type thermocouple connectors
• Contacts made from iron / constantan
• Durable nylon, color coded according to ANSI: Black
• Transmits the temperature signal from -292 to +1472 °F or -180 to +800 °C