It is one of the most common and well-known packing. It is made of a metal thin sheet and have special structure, there are two row window with ligules towards inside on the ring wall, each row window has five ligules bend to inside of the ring and point to center, at which the ligules touch each other, the position of up and down window is stagger, usually the area of window is about 30% of the whole ring area. The window on the ring wall let distribution and mass transfer efficiency of liquid and gas inside packing better than Raschig Ring.
