Chromenta offers 5 types of C18 HPLC columns depending on your applicatinos. KB-C18 is the standard column packed with high quality ultrapure type-B silica. KB-C18 has the widest selection of particle sizes from 1.8um UHPLC columns to 10um prep columns. KAQ-C18 is another standard column with excellent peak shape, in additon to being compatible with 100% aqueous solvent. EP-C18 has extended pH range stable from 2 to 12. BB-C18 has large pore sizes of 300A perfect for large peptide or protein analysis.