Kromasil HPLC Guard Cartridges Kromasil 300-5-C18 2.1 mm, 5 pc/PAK

A cartridge: This is the expendable column packed with the same packing as the HPLC column the user intends to protect. It's 1 cm long. Cartridges are sold in 5 and 3 pack for analytical and semi-preparative columns, respectively.