Bests & Worsts Reviews from Amazon

I use two of these for feral cat shelters and plan to add a third. The units are sturdy and well-made. Because my intended use is to provide warmth and shelter for ferals in winter weather, I made a few modifications. First, I insulated the inside of each shelter using the mylar bubble wrap insulate, including a double layer for the floor. I sealed the seams with duct tape to prevent air drafts. I then added straw (which retains heat and doesn't grow mold) so the cats can nest inside; I also added straw and styrofoam beneath each unit so there was a layer of warmth to prevent air drafts from beneath. The feral cats took to these fairly quickly and sleep in them consistently, both on wintry nights and sometimes even during the day. During the coldest temps, I also used "snugglesafe pet warmer" (available on amazon) which is a gel disc that can be microwaved and retains heat for 8 hours. These shelters, with a few added precautions, are keeping the ferals here safe and warm. I highly recommend this model (and kudos for having the second door so the animals can't get trapped by prey who could potentially block them inside).