Guard column for any Ultra C18 column (3um or 5um particle size) with 4.6mm ID. Pore size: 100A, surface area: 300 m2/g, 20% carbon load, endcapped. pH range 2.5-8.0, maximum temperature 80C. Requires Trident Level 2 holder (guard only) REST-27472 or Trident Level 3 holder (guard + filter) REST-27474.