IBM MX5 - Manual (Page 8)

Note: Until the Main Battery and Backup Battery are completely depleted, the
MX5 is always drawing power from the batteries (On).
MX5 Environmental Specifications
Operating
Temperature
-4°F to 122°F (-20°C to
50°C) [non-condensing]
Extended Op
Temperature
-22°F to 122°F (-30°C to
50°C) [non-condensing]
w/Heater option (see Note)
Storage
Temperature
-22°F to 158°F (-30°C to
70°C) [non-condensing]
Rating IEC IP67
Operating
Humidity
5% to 90% non-condensing
at 104°F (40°C)
Vibration Based on MIL Std 810F
Shock
75G, 5ms duration, 100
shock impacts
Note: If the MX5 has a dead Main Battery and is as cold as the extended
operating temperature’s lowest value, the unit must be warmed to above
–20°C (-4°F) before installing a new Main Battery pack and the system
powered on.