New surface modified submicron silicas produced by a hybrid production process are compared to commercially prepared surface-modified colloidal silica with respect to their applicability as external additives for electrophotographic toners. The principal metric for comparison is tribo-electrostatic charge (T-ESC) stability under an extended activation period, but relative dispersibility on toner and the influence of environmental extremes on tribo-charge properties are also examined. The hybrid materials have sufficient hydrophobicity and can work as spacer particles to prevent the embedding of small particle size external additives. Further characteristics and advantages for this new external additive type will be presented.