EZ MOUNT: K&H EZ Mount products mount to most glass windows for easy tool free cat window perch assembly LARGE SCRATCHER: Large curved surface is great for scratching or basking in the sun and free catnip is included CURVED: When kitty isn’t scratching, they have a nice, curved sleeping surface cats love during after play naps in the sunshine on their cat hammock DURABLE: K&H cardboard cat scratchers and refills are made of superior cardboard that lasts longer than other scratchers HEALTHY: Cat window sill encourages your cat to scratch something other than your furniture, keeping their nails healthy REFILLS: Two styles of refills are available separately for this product, the Kitty Sill Refill and the K&H EZ Mount Kitty Sill Cradle Refill(like this one); both fit this frame BRAND YOU TRUST: Designed by K&H with OVER 20 years of experience in creating safe, innovative, quality products for pets