Guard Column for 7.5mmID TSKgel G2000SW, G3000SW and G4000SW columns. TSKgel Guard Columns are stand-alone and do not require separate holders.. Parameter: =0.5 M salt concentration. Application(s): HPLC: suitable. Sold in each. . . Sigma-Aldrich 805371 TSKgel SW Type Guard Column, Phase Diol, 10 µm Particle Size, 7.5mm ID, 7.5cm Length. Country of Origin : United States. Part Number : 1186N53EA. Pack of : 1.