The long, skinny balloons known as animal, twisty, or pencil balloons are those designed specifically for sculpting; they come in various sizes depending on your creative needs. They are officially named with numbers that describe their width and length after they are inflated. The most commonly used balloon is the 260. The "2" refers to the width, which is approximately two inches in diameter, and the "60" refers to the length, which is approximately sixty inches, end to end. Most of the designs in this book require 260s, unless otherwise stated. In many cases, the 260 can be substituted with balloons of varying widths and lengths to create the same designs in smaller or larger scale.