When looking at the chair from the back, the B-Side upholstery is what is behind the criss cross Flex Net back support. It is 100% polyester and no frills. Your selection, however can give your chair some frills. It can make the back of the chair blend or add some contrast by making the two options match or not. If any of this is confusing, please reach out to our sales team at 888.467.6278, they know everything. Promise.