Let’s start with defining simplex. For that, I’ve turned to two great sources. My friend, Ellen Jacobson, President of Elila Lingerie, and Beverly Johnson, Author of "The Bra-Makers Manual" and a true expert in bra construction and fit. Beverly has written about simplex several times on her blog. True simplex is a nylon knit with a little stretch – not like nylon that’s combined with spandex. Molded simplex bra cups can stand on on their own – even in the bigger cup sizes – without needing interfacing or other fabrics fused or layered onto it. And, simplex tends to have a matte finish. Ellen takes the definition a little farther. She first points out that the word simplex in Asia or Europe simply means a knit or "tricot" fabric you see in bathing suit material but without the spandex.

However, simplex’s more correct definition is a type of knit that has a "V" shape pattern to it’s knit. This makes it great for molding to the body. And, because of this type of construction, rather than just stretching up and down, and left and right (known as a 2-way stretch), simplex has what is called a mechanical stretch – it can stretch in every direction. But, it also gives great support because the stretch is controlled and not overly stretchy. It’s more like our skin, it stretches a little in any direction, but bounces back and gives great support. So, seamless molded bra cups made in simplex will be light-weight, but hold your breasts firmly without sagging – even in the larger cup sizes. A simplex cup will feel like wearing a second skin because of it’s all around firm support that stretches to give your breasts a natural look.

Here are some bras using simplex fabric in their seamless cups:

The Fantasie Smoothing T-Shirt Bra style 4510

The Lilyette Technocomfort Unlined Bra style 947

Also, Olga company is also launching throughout 2008 several underwire and minimizer seamless cup styles that will be using molded simplex in the cups.

You can find bras made with Simplex on HerRoom.