... by this machine has the following advantages :average wall thickness ,smooth inner and outer wall ,good impermeability ,high compressive strength ,low cost ,firm ... mm): φ200, φ300, φ400, φ500, Ø600, 700, φ800, φ1000 (2)Wall Thickness: 200 30mm, φ300 30mm, φ400 40mm, φ500 50mm, 600 ...