Collaborative ottomans can be used together to create a wide variety of layouts. Frames are constructed with interlocking plywood jigsaw or stud construction. Joints reinforce each other for maximum stability. High resiliency CFC-free polyurethane foam. Fire retardant foam meets CAL 117 requirements. Units are standard with black adjustable floor glides. Manufactured with environmentally friendly preferred products (EPP). Greenguard Indoor Air Quality Certified.