Hisense BCD-440 User's Operation Manual page 11

NOTE:For optimum food preservation, we
recommend that when you start your
refrigerator for the first time, the
temperature for the refrigerator is set
to 4°C ,and the freezer to -18°C.
For optimum food preservation, a medium
setting is generally the most suitable.
NOTE:High temperature setting will
accelerate food waste.