Tampon design varies between companies and across product lines in order to offer a variety of applicators, materials and absorbencies.[10] Tampon applicators may be made of plastic or cardboard, and are similar in design to a syringe. The applicator consists of two tubes, an "outer", or barrel, and "inner", or plunger. The outer tube has a smooth surface to aid insertion and sometimes comes with a rounded end that is petaled.[11][12]