Double the fun of a window perch. The Kitty Sill - Double Stack EZ Window Mount™ by K&H is the perfect window mounted play/sleep area. Incorporating steel frames and our unique push ’n’ turn super strong suction cups, this window mounted gem is sure to please. As with the single unit, it can be folded up against the glass in seconds to allow for normal operation of blinds, curtains or shades. Covers easily remove for washing.