Use Standard Media Converter Switches in clean, temperaturecontrolled areas of +32 to +104° F (0 to +40° C), such as offices and closets.Hardened Media Converter Switches suit -13 to +140° F (-25 to +60° C) operation in dusty or dirty environments. Their sealed cases are a heat sink, so no internal airflow is needed for cooling, and they resist contaminants such as dust, dirt, and moisture.For harsher environments of -40 to +167° F (-40 to +75° C), choose Extreme Media Converter Switches. These rugged units are for outdoor use (they only require protection from water) and feature a sealed case, which uses its own metal shell as a heat sink.