Substance: Nylon, elastane What exactly is a Plunge Bra? A plunge bra might be the easiest bra to identify. Identified with the v-neckline, plunge bras have angled cups that help remove gaping though offering your breasts a little accentuation to get a thrust-up kind of glance, without any extra padding.9. Strapless: Wearing a tube or off-shoulder