The primary difference between Type J and Type K thermocouples is the measuring range, and the sensitivity. Type K is the most common general purpose thermocouple with a sensitivity of approximately 41 μV/°C. A wide variety of probes are available in its ?200 °C to +1350 °C / -330 °F to +2460 °F range. Type K wire color standard is yellow (+) and red (-). Type J has a more restricted range than type K (?40 to +750 °C), but higher sensitivity of about 50 μV/°C. Type J wire color standard is white (+) and red (-).