Lisbon Swivel Tub Chair In The Lisbon Collection By Lazzaro Lazzaro frames are constructed of kiln dried birch hardwood which is indigenous to the Shunde area and is virtually knot free and are glued and corner blocked for stability. A 5/8 thick plywood board is used in vertical support slates that attach the seating system to the outer frame. Leggett Platt sinuous springs are used in both seat and inside backs working in concert with our cushioning to create a comfort seating system and to ensure the seat cushions ride on a stable yet secure base. Pirelli elastic straps are woven side to side through the sinuous springs and affix to the frame to stabilize and prevent the springs from moving apart. In almost all of our designs the seat cushions are loose; they can be removed to vacuum clean the seat decking and if desired , to add additional Dacron cushion wrapping to refresh the seating look and feel in future years. Lazaro uses 1.9 to 2.5 density high quality foam cores for their seat cushions and wraps each cushion in a layer of long filament Dacron fiber to ensure a softly crowned cushion top on a foam foundation. Each cushion is wrapped in a gauze fabric casing. The insides of the back cushions are constructed of channeled or baffled casing pockets to prevent the Dacron fiber filling materials from migrating, thus crating a stabilized cushion appears and consistent comfort. Lazzaro uses only 100% US cowhide in our tannery. US hides are larger and have fewer defects than hides from South America. We offer solid color leathers with a slight waxy hand for our more contemporary designs as well as Vintage antiqued leather finishes for our more traditional models. We actually tan our own hides so we can monitor the quality and consistency. Frames are made of solid birch bolted in construction with corner blocks for maximum support, Seating system is made with sinuous springs and reinforced with Pirelli webbing and cores that have 2.0 2.5 foam density and decron