Chromatography Column HolderSize: 12¼ x 2½ in. for up to 8 1³⁄₁₆ in. ColumnsSecurely holds as many as eight chromatography columns up to 30mm (1³⁄₁₆") in diameter in or between its flexible loops.Rigid plastic back is mounted on two polyethylene support blocks which slide over support stand rodsTigh..