"Ceramic Raschig Rings" are an excellent column filling due to their large surface area.
0.5 liters (30.5 cu. in.)
6 mm x 6 mm x 1.5 mm

Raschig rings are a form of random packing and are used in commercial fractional distillation columns to reduce pressure loss (versus using trays), while maintaining good efficiency and economy. Typically the change in pressure (also called "delta p") is lower than in the case of trays but slightly higher than for structured packing. Raschig rings are named after the German chemist Friedrich August Fritz Raschig.