HALO columns are designed with 90 Ångstrom pores for small molecule analysis. They are made using 2.7-µm Fused-Core particles with a thin 0.5-µm outer porous shell to provide superior performance compared to totally porous particles. The 2.7-µm particle size also allows HALO columns to be used with both UHPLC and HPLC instrumentation for high speed or high resolution analyses. With a 2-µm inlet frit, HALO columns are excellent for R&D and routine analyses due to their ruggedness and reliability.