Product information: Material: Wood + Acrylic Size: Small - 9.84"(D) Middle - 11.8"(D) Large - 13.78"(D) Capsule Thickness - 0.2" Features: 1.Premium Quality capsule with good transparency, you can always pay attention to cat's activities. 2.The transparent acrylic provides a secure environment by giving the cat a much wider eyesight. 3.Mounted on the wall, allows the cat to be perched viewing from above. 4.With the shape of a capsule, provides larger space area for pet to sleep.