Denicotea Long Filter 10110 - These filters fit most Long Denicotea holders. Silica gel with its highly porous structure considerably reduces harmful effects. By changing color from clear white to dark brown the effect is clearly shown, and it indicates when the filter has to be changed. Denicotea are filters intended for use in Denicotea holders, not for use in tobacco pipes. Only the original Denicotea filter has the red cap!