Plastic coil (a.k.a. "plastic spiral") is popular for children's books, calendars and computer manuals. Like Wire-O, plastic coil elements are available in a wide variety of colors and sizes, but unlike Wire-O, they will spring back to their original shape even if stepped on. Plastic coil production is a semi-automatic process; long runs usually aren't economical. Since plastic coil bound pages step-up when opened, crossover images should be avoided.