Product review (5 stars): great inexpensive device
I bought the four pack because I wanted to scatter these around the house.  I might buy more!  For 5 bucks a unit, these things are awesome!  I even use one on the enclosed porch and it seems to work fine even though it's truly an outdoor space (goes below freezing regularly), it should stay dry in it's location and I can see it from indoors, so it gives me good info!  If it breaks, oh well, it's only 5 bucks!  I wish it had a min/max memory feature, but what can you expect for 5 bucks!  Simple but sweet!