this is wonderful add on to our back yard community, a variety of feral cats come in, during the harsh winters and acrtic blast this unit offered some much needed protection, in addition i added some heating pad and straw, the pads have built in safety switch to turn on/off and pressure switch that allows pad to turn on when animal is on the pad and cycles at safe temps. Next i will need to add some insulation and some feline screening to protect the insulation.