thermocouplestandards-platinum-platinumrhodiumvol1 (1) The measuring assembly comprises a 7mm x 300mm or 600mm gas tight 99.7% recrystallized alumina sheath inside which is a 2.5mm diameter twin bore tube holding the thermocouple. *The type R and S standards will cover the range from 0°C to 1600°C. *Type R and Type S *Gas Tight Assembly *Premium Grade Wire