(#C17) Thermocouple Gaskets are made specifically for Ecklund Needle Thermocouples. A needle thermocouple is inserted through a gasket, which can then be used to provide a seal and cushion for the thermocouple when it is installed into a receptacle. Thermocouple gaskets are rubber and have an inner diameter of 3/16" (5 mm) and an outer diameter of 5/16" (8 mm).