Underwires are sewn-in molding that run under the cups of a bra. They can be constructed of flexible plastic, coated wire or molded plastic. Underwire bras are among the most popular front close bras on the market because of the support and lift they provide. In fact, for women who wear a C cup or larger, underwire bras should their first consideration since larger breasts need support to keep them from sagging or having the uni-boob look.
While front-close underwire bras are popular, they need to be fitted carefully. The wire should rest smoothly against the sternum and not lay on breast tissue. Add to that the relative lack of adjustability of front closing bras and fit becomes paramount. However, when an underwire front-close bra fits correctly, it has the advantages of great support and lift as well as the convenience of fastening in front.