The openings on the cylinder wall let the pall ring make full use of the inner surface and improve the separating and absorbing efficiency. The flux of pall ring improves 50% than the Raschig ring but the pressure drop reduce half.

The material of pall ring is commonly metal, plastic and ceramic. Metal pall ring can be stainless steel, carbon steel and other alloy steel. They have outstanding corrosion and rust resistance performance in the chemical and other harsh using environments. The plastic pall ring has outstanding temperature resistance, it can remain perfect condition no matter in the subzero or high temperature environments. The ceramic pall ring has thicker thickness than the metal or plastic pall ring. It may has high absorbing efficiency in all conditions.