CASELLA CEL CEL-450 Handbook page 11

At the end of the self test sequence, the instrument displays
memory information and battery voltage,
followed by the identity of the last used setup.
Finally it enters calibration check mode (described in Chapter 2).
CEL-450/490 Operators Handbook - Page 11
Introduction
Inst. Type 450/490
Inst. Version A = Broadband
B = Octave band
C = Third octaves
1 = Class 1
2 = Class 2
Firmware version
Program version and issue
Interface status
Inst. identification number
Current date and time
Last used setup
The dates and times of the last 4
calibrations are stored.
See Section 2.2.