Inner frame: steel structure inner frame, stable structure and long service life; Sponge: Polyurethane PU one-time foam die-casting molding cotton, the density is as high as 50KG/m³, and it will not deform after sitting for a long time; Fabric: The leather surface feels fine, good toughness and elasticity, high anti-friction coefficient, soft fabric, high resilience, not easy to pilling, pure col