Natural Materials. This wood cat tree is made of Oak, Kraft Paper Pillar, 8 cm Natural Sisal Rope, Handwork Ma Teng Cat's Nest with crafted workmanship, Ensuring long service life. Each scratching post is covered by natural sisal ropes that cats can scratch to protect your delicate furniture. In addition. Stronger Props for Bigger Cats. The cat tower for indoor cats measures 21.7 x 54 x 21.7 (W x H x D) and equipped with multiple big sisal scratching posts (3.15 inch), That can not only hold up to 10 lbs, but also ensure safety to hold all platforms firmly without any wobbling from scratches.