An iron core under Japanese sisal. The core is why it does not wobble - the whole structure holds still under a cat at full speed.

66.1 inches (5 ft 6 in) tall on a 23.6 by 21.6 inch base. Six tiers, a 15.7 inch resting platform, a 15 by 9.8 inch nest, and an 18.9 by 15 inch hammock. Rated to 30 lbs.

Six levels give a cat somewhere to scratch, climb and watch from that is not the arm of a sofa.

Ships flat. One person can put it together in about 30 minutes, and instructions are included.