WH31_EP monitor the Temp & Humidity only,
and supports 8 channels in one console
(You can add WH31 maxum 8 units to work with one gateway/hub/console).
WH32_EP outdoor coded supports one channel only to connect console, for there are complex algorithm to calculate Feels Like, App Temp and Dew Point.
It's design for replace data of WS69 WS80 WS90 or upgrade WS68 WH40.