Kromasil guard columns are built of 3 parts:

• 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.
• A holder: A stainless steel container for the cartridge.
• A coupler: A PEEK connector or a short capillary tubing (for larger prep columns) to attach the guard column at the inlet of the HPLC column.

A Guard starter kit for analytical columns contains one holder, one coupler and a 5 pack of cartridges of the actual silica packing.

Click on link for more info.