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RH25: Heat Index Psychrometer

Compact indoor/outdoor meter for measuring up to 6 environmental parameters

View Datasheet > RH25


Extech’s pocket-sized Heat Index Psychrometer Pen easily monitors Heat Index during hot humid days to prevent heat stroke during outdoor activities, sporting events or, indoor workplace. Its pen-sized design makes it convenient to fit into your pocket and carry it wherever you go. Complete with CR2032 battery.

Additional information


-4 to 122°F (-20 to 50°C)

Relative Humidity

0 to 99.9%RH

Wet Bulb

-4 to 122°F (-20 to 50°C)

Dew Point

-108.4 to 122°F (-78 to 50°C)

Heat Index

-50.8 to 401°F (-46 to 205°C)


5.5×1.4×0.7" (140x35x18mm)


1.8oz (50g)

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