What is open bra cup?

Open bra cups, also known as shelf bras or quarter cup bras, are a type of bra that leaves the top half of the breasts exposed. The cups are usually made of a thin material and are designed to support the lower part of the breasts. Open cup bras come in various styles, including underwire, lace, and harness. They are often worn as a erotic lingerie or as a fetish wear and can be paired with a variety of outfits. Open bra cups give a woman a highly desirable, sexy look, and they are great for women who want to add some spice to their lingerie collection. However, they are not typically comfortable or supportive enough to be worn on a daily basis.