Comparison Chart: Count1Schwarzkopf Igora Royal Developer - Color : 3% / 10 Vol 33.8 fl.oz.1Schwarzkopf Igora Royal Developer (Color : 6% / 20 Vol)1Schwarzkopf Igora Royal 6% 20 Vol. Colorist's Color & Care Developer 33.8 oz (1 Liter)1"Schwarzkopf Igora Royal Developer, 3% / 10 Volume...