Ceramic raschig rings are a low-cost but highly effective material for packing a reflux column. It is typically recommend to use 1 pound of copper mesh and 1 liter of ceramic raschig rings to pack a 2 or 3 inch column. The copper helps remove the sulfides, and the raschig rings are much cheaper on a per volume basis then copper. Raschig Rings also have a longer lifespan then copper.