Set of 4 Replacement Giant Suction Cups and 2 Shims for all Kitty Cot Originals. Even works for most imported cat window perches to replace their cheap suction cups. Kitty Cots attach to glass windows using PATENTED Giant Suction Cups, made in the USA. They really are amazing! Each suction cup is rated to hold 12 pounds therefore we can safely say it will hold up to 25 lbs. of Kittycat(s). Kitty Cots come in 3 sizes to fit various size window widths and preferences, Small, Medium and Large. Large Kitty Cots measure 25-1/2″ wide (from outside to outside of suction cups) x 14″ deep. Medium Kitty Cots measure 22-1/2″ wide (from outside to outside of suction cups) x 14″ deep. Small Kitty Cots measure 19-1/2″ wide (from outside to outside of suction cups) x 14″ deep. The Kitty Cot frame is made of strong and durable plastic pipe. The hammock is made of tough weather-resistant fabric, an “easy clean” comfy material that your cats will love. Quickly take the Kitty Cot down for easy cleaning. The Kitty Cot can go on a glass window or even mirror anywhere in your house and at any height. Kitty Cots work indoors and outdoors. Our design is so simple and easy that anyone can put it up and best of all, you need no tools to install it. Lay your cat's favorite blanket down to make it even more bed-like and comfortable.