Why didn't someone think of this sooner? Designed to hang on any standard door in your home, the Cat Climber from SmartCat is the perfect choice for smaller homes or people who don't want to swap an end table for a traditional cat tree. Now your cat can scratch, play, sleep, and exercise safely on this patented product. The climber is easily moved from door to door because of its spring loaded bracket system. The natural sisal post is ideal for scratching. Made of durable wood, the climber will withstand years of use. I have three in my house, one for each cat, says designer Angela Moser. Our cats love it when we move them around the house, it’s like a new adventure for them.