... strong restoring function.The back cushion is made of cold polyurethane foam sponge and high-quality plywood.Designed sponge image according to ... the human scicence principle.Durable,Ametabolic,the Density of foam reach 55kg-65/m3.2.Plastic seating board:High- ... composite materials.Paired with an internal layer of sound-absorbing foam,acoustical seat pans enrich the sound and augment the audience ...