Product review (1 stars): It worked perfectly for about 5 months (and one battery ...
It worked perfectly for about 5 months (and one battery change), then spontaneously the outdoor transmitter failed completely and will no longer transmit.  There's no replacement part to be found so you'd have to buy the whole unit all over again.  As an indoor thermometer, it might still be usable, except that you can't make the smaller indoor temperature/humidity the larger 2 numbers.