Glass column, 350 mm × 20 mm fitted with sintered glass plug

Insert a plug of glass wool into the lower end of a glass column (4.3).

Glass column (300 mm x 10 mm) fitted with a sintered-glass filter and a stopcock

Insert a small glass-wool plug into the lower end of a glass column (4.1) and tamp it down using a glass rod.

Glass column (length 300 to 400 mm, internal diameter approximately 10 mm) with sintered glass frit and draw-off valve.