Omega Engineering OST-K-F - Standard Thermocouple Connector, Round Pin, 2 Pins, Female, K Type, -29 C to 180 C (-20 F to 356 F), ANSI, OST Series
With a legacy design, whenever it is the only choice it is plug compatable with the OSTW standard size round pin connectors or any other similar round pin male TC plug or Female TC jack.