The first component of the PetSafe wireless fence is the transmitter, which typically is mounted inside a building like a home or a garage.
It should not be exposed to any rain or sprinklers.
They can be kept in a plastic waterproof case as long as there is enough ventilation to allow the unit to cool.
It will malfunction if it overheats, so the case should also be in the shade.
PetSafe transmitters need to be plugged into an outlet and therefore will not be able to withstand any water because of this open power source and electronics.
It is a serious shock hazard.