... Rating: 0.4MPa, 0.6MPa, 0.8MPa, 1.0MPa, Plastic corrugated pipe for drainage Physical-mechanical characteristic: ItemsIndexTesting MethodRing stiffnessSN8≥8GB/T9647-2003SN12 ... inner diameter):200mm, 225mm, 300mm, 400mm, 500mm, 600mm, 700mm ,800mm Plastic corrugated pipe