Dark ash brown is the one you want. My experience of this product is that, ideally, it should be used from the word `Go`, on your new system, as a maintenance product and to prevent oxidation [colour-lift] It`s less effective once more severe colour-lift has already happened, as it tends to wash out again, reasonably soon. Once that happens, you`re best off using an over-the-counter colouring product.... L`oreal make many as do other companies...apply a small amount along the teeth of a comb [don`t overload the comb] and comb it into damp hair....keep it off the lace, or you`ll stain it permanently. Ignore the ` timing` instructions on the pack...... system hair absorbs colour much much faster than growing hair, so only leave it on for about 3 minutes max.,otherwise it`ll go far too dark . Rinse it off under running water [such as a shower-head] by directing the water through the underside of the system, away from the lace.