Corner-blocked frame Loose seat cushion High-quality foam cushions wrapped in poly fiber Polyester upholstery Back pillows included Pillows with soft polyfill 360-degree swivel Platform foundation system resists sagging 3x better than spring system after 20,000 testing cycles by providing more even support Smooth platform foundation maintains tight, wrinkle-free look without dips or sags that can occur over time with sinuous spring foundations