For protection of your main HPLC column from contamination, it is recommended to use guard columns. These short columns are placed into a guard column holder. The guard column holder in combination with a guard column inside is installed between the injector and the HPLC column. This installation prevents chemical impurities to reach the main column. Because a contamination could form an irreversible bond with the column packing material (stationary phase) and this can result in shorter column life. If you want to prolong the lifetime of your main column, then these short columns can help you.