What are the specifications of PVC-m double-wall corrugated pipe, PVCm double-wall corrugated pipe and PE double-wall corrugated pipe specifications are the same, 110 and 160 mm for the outer diameter, 225 to 1000 mm for the inner diameter; ring stiffness is 8, 10, 12.5 and 16 kN, the specific specification table I posted at the back.