How can you check the last calibration data on the LTX multi-gas detector?

To check the last calibration data on the LTX multi-gas detector, pressing the on/off mode until "instrument calibration due" appears is the correct approach. This action typically triggers the display of relevant calibration information, including when the last calibration was performed and whether the instrument is due for recalibration, which is crucial for ensuring accurate readings.

The other methods, while potentially relevant for other operations or indications, do not directly facilitate the retrieval of last calibration data. Accessing the settings menu may provide various configuration options but might not explicitly show the last calibration status. Waiting for "last calibration" to appear might not be a recognized method for that specific device, while physically inspecting the detector for signs of age is too vague and does not directly relate to checking calibration data.