When looking at the chair from the back, the Flex Net is the criss cross support system you see. The material is high performance bio-based elastomer. Essentially, between the Flex Net and the B-Side upholstery (what is behind it as a backer) you can make it blend or add some contrast. If any of this is confusing, please reach out to our sales team at 888.467.6278, they know everything. Promise.