Extech RH25  

Extech RH25: Heat Index Psychrometer

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

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.