This X-Small swing is made from natural Bottle Brush wood which is a hardwood. The swing is loaded with 1 1/4" x 1 1/4" x 5/8" colorful Pine wood squares with wood balls on Stainless Steel Wire and will provide endless chewing for your little one. Inside height is 5 1/4" and overall width and height is 7 1/2". Diameter of branch is very small so would be best for parakeets, lovebirds or similar size birds.