User's Guide Digital Calibrator/Thermometer CL23A, 24, 25, 26, 27

If the unit is turning on for the first time after a new battery is installed, it will
automatically default to the METER mode (ie. temperature measurement
operation). It also defaults to K-type thermocouples, and °F readings with
0.1° resolution. The corresponding LCD annunciators are enabled:
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Figure 3. Display Test
Figure 2. Keypad