This listing is for 5 sets of Miniature J-Type Thermocouple connectors, one male connector and one female connector each per set. They conform to the miniature connector dimensions (10mm or 7/16 inch spade type) and the J-Type thermocouple wire specification. The metal blades are made fom the J-type thermocouple metals, iron and constantan. Use a pair of these mini j-type connectors to build thermocouple extension wires or to patch a broken thermocouple wire connection. The plugs have small holes in the center, this allows you to secure them using a cable binder or string, or you can screw them to equipment.