This bra is liked by most ladies as it gives excellent definition to the bust line. Underwire brassieres have a metal, plastic or wire support running underneath each cup which provides additional support and durability.
Right till the end of World War II, bras conventionally had soft cups and no wires. The underwire invention changed the industry to a great extent, by creating bras that had less breast coverage and yet good support. They give the fabric a stronger base to hold your bosom. If you can't do without your push-up, strapless or demi cup bras you should thank the underwire creator that made developing these beneficial brassieres possible.
Keep in mind: While trying on underwire bras, always check that it never touches the breast tissue. It must only touch the ribcage.