Each woman's breast structure is different. The variety of breast structures has led to the variety of bras. The bras that women use through out the day, which are underwear products, are selected according to breast structure, size and outfit. In daily life, women who care more about their comfort prefer bras without support. Bra without push-up models are bras without underwire and without filling. In general, women with fuller breasts prevent their breasts from appearing larger than they are in non-underwired bra models. Underwire bra models support the breast from below, making them appear more upright. For this reason, bras without underwire should be used by women who are not sagging and have a more unified chest.