1000ml iNOA mixes in a 1:1 ratio with 10-Vol, 20-Vol and 30-Vol. iNOA Rich Developer. iNOA Rich Developer is formulated to be paired with iNOA for best results.1 Liter/33.8oz. = 16 applications. 95% of women choose iNOA. What it does: 10-vol. iNOA Rich Developer pairs with iNOA for: Darken a naturally light base color, to color to the same level, to take-through mid-lengths and ends, and for pre-coloring. Lifts up to 1 level. 20-vol. iNOA Rich Developer pairs with iNOA for: Coverage of white hair. Lifts up to 2 level. 30-vol. iNOA Rich Developer pairs with iNOA to: Darken a naturally light base color, to color to the same level, to take-through mid-lengths and ends, and for pre-coloring. How to use: Mix ratio 1:1 (1 tube : 2.6 oz. developer). Apply with a bowl and brush or plastic bottle. Development time up to 35 minutes.