GARNIER COLOR SENSATION COLOR RETOUCH HAIR DYE "ROOT RETOUCH IN 10 JUST MINUTES: No ammonia for a pleasant smell. Up to 4 weeks of root coverage. Up to 100% grey coverage. Experience a mess-free application with its non-dripping formula as easy to apply as shampoo. EASY TO USE SACHET FORMAT: Mix colourant & developer sachets directly in your hands and apply on visible roots with fingers . In need of a length colour boost? Apply on lengths and refresh your hair colour. IDEAL AMOUNT FOR 1 APPLICATION : The sachet format is perfectly dosed to allow you to easily cover your visible roots or to refresh your lengths.CHOOSE YOUR SHADE: 8 universal shades to refresh your hair colour. Pick the shade that is the closest to yours and use to touch up your roots regardless of the hair dye brand you currently use.How to useEASY TO USE SACHET FORMAT: Mix colourant & developer sachets directly in your hands and apply on visible roots with fingers. In need of a length colour boost? Apply on lengths and refresh your hair colour."Seems extremely easy to use and should last 4 weeks once applied apparently.