The TGP-4510 monitors Temperatures from -40 to +85°C (-40°F to +185°F) using a built-in sensor, and has a connection for one of our range of thermistor probes for monitoring from -40 to +125°C (-40°F to +257°F). With a built in sensor and a probe, this versatile unit is ideal for comparison of, for example, ambient and process temperatures.