PRESIDIUM Duo Tester Mode D'emploi page 13

Recommended testing conditions
The gemstone should be clean and dry before testing.
However, elaborate cleaning procedures are not normally
necessary (Fig. 1.6).
Fig. 1.6
The recommended testing temperature is 18°C – 27°C or
65°F- 80°F. Please allow the gemstone or jewelry piece to
adjust to room temperature prior to testing. Exposure and/
or operation of the tester outside the room temperature
would affect the results and performance of the tester.
Battery information
Do not leave worn out batteries in the battery
compartment as the batteries may corrode, leak, and
damage the tester. Batteries should be removed when the
tester is expected to be stored for any extended period of
time.
Batteries do not have to be removed when the AC adaptor
is in use.
To prevent inaccurate readings, replace with new batteries
if the red LED does not light up after 20 seconds. A test
should not be performed when the battery is low or weak.
13