I use a Lacrosse one as well...usually set the transmitter in the shade somewhere under the slide. Mine keeps a record of the lowest and highest temp recorded, and I can reset that with a press of a button if I want to monitor temps on a particular trip. Its pretty interesting to see how hot it can get in the trailer in summer time when it's parked at
home in between trips. In the off season when the trailer is stored, I use it at the house to monitor our winter chills...tonight it's reading 15F...and thats a warming trend!
I have had to change the batteries once in 2 years.