The JW® Sand Perch Swing is specially designed for your pet bird's well-being. Your feathered friend is sure to get a great workout with this perch swing as he exercises the muscles in his feet. Rough texture provides an excellent surface for normal wear of your pet bird's nails. This swing easily attaches to cage ceiling wire. Small is sized right for parakeets and similar sized birds. Regular is sized right for cockatiels and similar sized birds.