It's a simple box about 8" (20 cm) high covered with four towels. He'd lay on the floor there but that put him below the heat stream so he'd have to sit with his face into the screen to get warm. Now he sleeps on the box for hours and gets quite toasty. Abys don't really put on a winter coat so they really crowd in bed at night (they are routinely cuddly anyway but when it's cold it becomes an imperative!).