Underwire construction is the most common method of support in bra design. Underwire is not always literally wire, although it can be. Modern materials include flexible plastic or wire, plastic-coated metal or molded plastic. The underwire is sewn between layers of fabric under the cups of the bra and supports the breasts as well as providing lift and separation. Modern polyfibers allow for bra cups that can be completely seamless, molded from one piece of fabric. Coupled with underwire construction, a seamless underwire bra will be smooth under clothing, creating a youthful shapely silhouette with lots of support. Style options are virtually limitless--from minimizers to push-up, and demi cups to full-coverage. A few supportive seamless bras should be a staple in your lingerie wardrobe.